diff --git a/app/main.ts b/app/main.ts
index bfdd37e094..55a395dbb5 100644
--- a/app/main.ts
+++ b/app/main.ts
@@ -675,7 +675,7 @@ async function createWindow() {
       nodeIntegration: false,
       nodeIntegrationInWorker: false,
       sandbox: false,
-      contextIsolation: false,
+      contextIsolation: !isTestEnvironment(getEnvironment()),
       preload: join(
         __dirname,
         usePreloadBundle
@@ -1138,7 +1138,7 @@ async function showScreenShareWindow(sourceName: string) {
       ...defaultWebPrefs,
       nodeIntegration: false,
       nodeIntegrationInWorker: false,
-      sandbox: false,
+      sandbox: true,
       contextIsolation: true,
       preload: join(__dirname, '../ts/windows/screenShare/preload.js'),
     },
@@ -1192,7 +1192,7 @@ async function showAbout() {
       ...defaultWebPrefs,
       nodeIntegration: false,
       nodeIntegrationInWorker: false,
-      sandbox: false,
+      sandbox: true,
       contextIsolation: true,
       preload: join(__dirname, '../ts/windows/about/preload.js'),
       nativeWindowOpen: true,
@@ -1240,7 +1240,7 @@ async function showSettingsWindow() {
       ...defaultWebPrefs,
       nodeIntegration: false,
       nodeIntegrationInWorker: false,
-      sandbox: false,
+      sandbox: true,
       contextIsolation: true,
       preload: join(__dirname, '../ts/windows/settings/preload.js'),
       nativeWindowOpen: true,
@@ -1379,7 +1379,7 @@ async function showDebugLogWindow() {
       ...defaultWebPrefs,
       nodeIntegration: false,
       nodeIntegrationInWorker: false,
-      sandbox: false,
+      sandbox: true,
       contextIsolation: true,
       preload: join(__dirname, '../ts/windows/debuglog/preload.js'),
       nativeWindowOpen: true,
@@ -1443,7 +1443,7 @@ function showPermissionsPopupWindow(forCalling: boolean, forCamera: boolean) {
         ...defaultWebPrefs,
         nodeIntegration: false,
         nodeIntegrationInWorker: false,
-        sandbox: false,
+        sandbox: true,
         contextIsolation: true,
         preload: join(__dirname, '../ts/windows/permissions/preload.js'),
         nativeWindowOpen: true,
@@ -1784,7 +1784,7 @@ app.on('ready', async () => {
         webPreferences: {
           ...defaultWebPrefs,
           nodeIntegration: false,
-          sandbox: false,
+          sandbox: true,
           contextIsolation: true,
           preload: join(__dirname, '../ts/windows/loading/preload.js'),
         },
diff --git a/background.html b/background.html
index 0e22129179..9980afcfd3 100644
--- a/background.html
+++ b/background.html
@@ -118,22 +118,6 @@
         .addEventListener('dblclick', () => window.showDebugLog());
     </script>
 
-    <script type="text/javascript" src="js/components.js"></script>
-    <script type="text/javascript" src="ts/set_os_class.js"></script>
-    <script
-      type="text/javascript"
-      src="ts/manage_full_screen_class.js"
-    ></script>
-    <script
-      type="text/javascript"
-      src="ts/backbone/reliable_trigger.js"
-    ></script>
-
-    <script
-      type="text/javascript"
-      src="ts/shims/showConfirmationDialog.js"
-    ></script>
-
     <!--
     Note: this inline script cannot be changed without also changing the hash in
     the CSP at the top of this file
diff --git a/components/webaudiorecorder/lib/WebAudioRecorder.js b/components/webaudiorecorder/lib/WebAudioRecorder.js
deleted file mode 100644
index 052abb858e..0000000000
--- a/components/webaudiorecorder/lib/WebAudioRecorder.js
+++ /dev/null
@@ -1,199 +0,0 @@
-(function(window) {
-  // internal: same as jQuery.extend(true, args...)
-  var extend = function() {
-    var target = arguments[0],
-        sources = [].slice.call(arguments, 1);
-    for (var i = 0; i < sources.length; ++i) {
-      var src = sources[i];
-      for (key in src) {
-        var val = src[key];
-        target[key] = typeof val === "object"
-          ? extend(typeof target[key] === "object" ? target[key] : {}, val)
-          : val;
-      }
-    }
-    return target;
-  };
-
-  var WORKER_FILE = {
-    wav: "WebAudioRecorderWav.js",
-    ogg: "WebAudioRecorderOgg.js",
-    mp3: "WebAudioRecorderMp3.js"
-  };
-
-  // default configs
-  var CONFIGS = {
-    workerDir: "/",     // worker scripts dir (end with /)
-    numChannels: 2,     // number of channels
-    encoding: "wav",    // encoding (can be changed at runtime)
-
-    // runtime options
-    options: {
-      timeLimit: 300,           // recording time limit (sec)
-      encodeAfterRecord: false, // process encoding after recording
-      progressInterval: 1000,   // encoding progress report interval (millisec)
-      bufferSize: undefined,    // buffer size (use browser default)
-
-      // encoding-specific options
-      wav: {
-        mimeType: "audio/wav"
-      },
-      ogg: {
-        mimeType: "audio/ogg",
-        quality: 0.5            // (VBR only): quality = [-0.1 .. 1]
-      },
-      mp3: {
-        mimeType: "audio/mpeg",
-        bitRate: 160            // (CBR only): bit rate = [64 .. 320]
-      }
-    }
-  };
-
-  // constructor
-  var WebAudioRecorder = function(sourceNode, configs) {
-    extend(this, CONFIGS, configs || {});
-    this.context = sourceNode.context;
-    if (this.context.createScriptProcessor == null)
-      this.context.createScriptProcessor = this.context.createJavaScriptNode;
-    this.input = this.context.createGain();
-    sourceNode.connect(this.input);
-    this.buffer = [];
-    this.initWorker();
-  };
-
-  // instance methods
-  extend(WebAudioRecorder.prototype, {
-    isRecording: function() { return this.processor != null; },
-
-    setEncoding: function(encoding) {
-      if (this.isRecording())
-        this.error("setEncoding: cannot set encoding during recording");
-      else if (this.encoding !== encoding) {
-        this.encoding = encoding;
-        this.initWorker();
-      }
-    },
-
-    setOptions: function(options) {
-      if (this.isRecording())
-        this.error("setOptions: cannot set options during recording");
-      else {
-        extend(this.options, options);
-        this.worker.postMessage({ command: "options", options: this.options });
-      }
-    },
-
-    startRecording: function() {
-      if (this.isRecording())
-        this.error("startRecording: previous recording is running");
-      else {
-        var numChannels = this.numChannels,
-            buffer = this.buffer,
-            worker = this.worker;
-        this.processor = this.context.createScriptProcessor(
-                                this.options.bufferSize,
-                                this.numChannels, this.numChannels);
-        this.input.connect(this.processor);
-        this.processor.connect(this.context.destination);
-        this.processor.onaudioprocess = function(event) {
-          for (var ch = 0; ch < numChannels; ++ch)
-            buffer[ch] = event.inputBuffer.getChannelData(ch);
-          worker.postMessage({ command: "record", buffer: buffer });
-        };
-        this.worker.postMessage({
-          command: "start",
-          bufferSize: this.processor.bufferSize
-        });
-        this.startTime = Date.now();
-      }
-    },
-
-    recordingTime: function() {
-      return this.isRecording() ? (Date.now() - this.startTime) * 0.001 : null;
-    },
-
-    cancelRecording: function() {
-      if (this.isRecording()) {
-        this.input.disconnect();
-        this.processor.disconnect();
-        delete this.processor;
-        this.worker.postMessage({ command: "cancel" });
-      } else
-        this.error("cancelRecording: no recording is running");
-    },
-
-    finishRecording: function() {
-      if (this.isRecording()) {
-        this.input.disconnect();
-        this.processor.disconnect();
-        delete this.processor;
-        this.worker.postMessage({ command: "finish" });
-      } else
-        this.error("finishRecording: no recording is running");
-    },
-
-    cancelEncoding: function() {
-      if (this.options.encodeAfterRecord)
-        if (this.isRecording())
-          this.error("cancelEncoding: recording is not finished");
-        else {
-          this.onEncodingCanceled(this);
-          this.initWorker();
-        }
-      else
-        this.error("cancelEncoding: invalid method call");
-    },
-
-    initWorker: function() {
-      if (this.worker != null)
-        this.worker.terminate();
-      this.onEncoderLoading(this, this.encoding);
-      this.worker = new Worker(this.workerDir + WORKER_FILE[this.encoding]);
-      var _this = this;
-      this.worker.onmessage = function(event) {
-        var data = event.data;
-        switch (data.command) {
-          case "loaded":
-            _this.onEncoderLoaded(_this, _this.encoding);
-            break;
-          case "timeout":
-            _this.onTimeout(_this);
-            break;
-          case "progress":
-            _this.onEncodingProgress(_this, data.progress);
-            break;
-          case "complete":
-            _this.onComplete(_this, data.blob);
-            break;
-          case "error":
-            _this.error(data.message);
-        }
-      };
-      this.worker.postMessage({
-        command: "init",
-        config: {
-          sampleRate: this.context.sampleRate,
-          numChannels: this.numChannels
-        },
-        options: this.options
-      });
-    },
-
-    error: function(message) {
-      this.onError(this, "WebAudioRecorder.js:" + message);
-    },
-
-    // event handlers
-    onEncoderLoading: function(recorder, encoding) {},
-    onEncoderLoaded: function(recorder, encoding) {},
-    onTimeout: function(recorder) { recorder.finishRecording(); },
-    onEncodingProgress: function (recorder, progress) {},
-    onEncodingCanceled: function(recorder) {},
-    onComplete: function(recorder, blob) {
-      recorder.onError(recorder, "WebAudioRecorder.js: You must override .onComplete event");
-    },
-    onError: function(recorder, message) { console.log(message); }
-  });
-
-  window.WebAudioRecorder = WebAudioRecorder;
-})(window);
diff --git a/package.json b/package.json
index b691b7d4cd..c226d3466a 100644
--- a/package.json
+++ b/package.json
@@ -16,14 +16,14 @@
     "postinstall": "yarn build:acknowledgments && patch-package && yarn electron:install-app-deps && rimraf node_modules/dtrace-provider",
     "postuninstall": "yarn build:acknowledgments",
     "start": "electron .",
-    "generate": "npm-run-all build-protobuf build:esbuild sass get-expire-time copy-and-concat",
+    "generate": "npm-run-all build-protobuf build:esbuild sass get-expire-time copy-components",
     "build-release": "yarn run build",
     "sign-release": "node ts/updater/generateSignature.js",
     "notarize": "echo 'No longer necessary'",
     "get-strings": "node ts/scripts/get-strings.js",
     "push-strings": "node ts/scripts/push-strings.js",
     "get-expire-time": "node ts/scripts/get-expire-time.js",
-    "copy-and-concat": "node ts/scripts/copy-and-concat.js",
+    "copy-components": "node ts/scripts/copy.js",
     "sass": "sass stylesheets/manifest.scss:stylesheets/manifest.css stylesheets/manifest_bridge.scss:stylesheets/manifest_bridge.css",
     "build-module-protobuf": "pbjs --target static-module --force-long --no-verify --no-create --wrap commonjs --out ts/protobuf/compiled.js protos/*.proto && pbts --out ts/protobuf/compiled.d.ts ts/protobuf/compiled.js",
     "clean-module-protobuf": "rm -f ts/protobuf/compiled.d.ts ts/protobuf/compiled.js",
@@ -190,7 +190,7 @@
     "@babel/preset-typescript": "7.17.12",
     "@electron/fuses": "1.5.0",
     "@mixer/parallel-prettier": "2.0.1",
-    "@signalapp/mock-server": "2.12.0",
+    "@signalapp/mock-server": "2.12.1",
     "@storybook/addon-a11y": "6.5.6",
     "@storybook/addon-actions": "6.5.6",
     "@storybook/addon-controls": "6.5.6",
@@ -229,7 +229,6 @@
     "@types/lru-cache": "5.1.0",
     "@types/memoizee": "0.4.2",
     "@types/mocha": "9.0.0",
-    "@types/mustache": "4.1.2",
     "@types/node": "16.18.3",
     "@types/node-fetch": "2.6.2",
     "@types/normalize-path": "3.0.0",
diff --git a/test/index.html b/test/index.html
index 6c8efb8f0f..fa21a42418 100644
--- a/test/index.html
+++ b/test/index.html
@@ -11,53 +11,10 @@
   <body>
     <div id="mocha"></div>
     <div id="tests"></div>
-
-    <script type="text/javascript" src="../js/components.js"></script>
-    <script
-      type="text/javascript"
-      src="../ts/backbone/reliable_trigger.js"
-    ></script>
     <script
       type="text/javascript"
       src="../node_modules/mocha/mocha.js"
     ></script>
-    <script type="text/javascript">
-      mocha.setup('bdd');
-    </script>
     <script type="text/javascript" src="test.js"></script>
-
-    <script type="text/javascript">
-      window.Signal.conversationControllerStart();
-
-      window.testUtilities.prepareTests();
-      delete window.testUtilities.prepareTests;
-
-      !(function () {
-        const passed = [];
-        const failed = [];
-
-        class Reporter extends Mocha.reporters.HTML {
-          constructor(runner, options) {
-            super(runner, options);
-
-            runner.on('pass', test => passed.push(test.fullTitle()));
-            runner.on('fail', (test, error) => {
-              failed.push({
-                testName: test.fullTitle(),
-                error: error?.stack || String(error),
-              });
-            });
-
-            runner.on('end', () =>
-              window.testUtilities.onComplete({ passed, failed })
-            );
-          }
-        }
-
-        mocha.reporter(Reporter);
-
-        mocha.run();
-      })();
-    </script>
   </body>
 </html>
diff --git a/test/test.js b/test/test.js
index 32da00cf9f..ae63520621 100644
--- a/test/test.js
+++ b/test/test.js
@@ -7,6 +7,7 @@
  * global helpers for tests
  */
 
+mocha.setup('bdd');
 mocha.setup({ timeout: 10000 });
 
 function deleteIndexedDB() {
@@ -38,7 +39,34 @@ before(async () => {
   await window.storage.fetch();
 });
 
-window.Whisper = window.Whisper || {};
-window.Whisper.events = { ...Backbone.Events };
+window.textsecure.storage.protocol = window.getSignalProtocolStore();
 
-window.textsecure.storage.protocol = new window.SignalProtocolStore();
+window.testUtilities.prepareTests();
+delete window.testUtilities.prepareTests;
+
+!(function () {
+  const passed = [];
+  const failed = [];
+
+  class Reporter extends Mocha.reporters.HTML {
+    constructor(runner, options) {
+      super(runner, options);
+
+      runner.on('pass', test => passed.push(test.fullTitle()));
+      runner.on('fail', (test, error) => {
+        failed.push({
+          testName: test.fullTitle(),
+          error: error?.stack || String(error),
+        });
+      });
+
+      runner.on('end', () =>
+        window.testUtilities.onComplete({ passed, failed })
+      );
+    }
+  }
+
+  mocha.reporter(Reporter);
+
+  mocha.run();
+})();
diff --git a/ts/CI.ts b/ts/CI.ts
index 63d8bfc300..7e3aa1834f 100644
--- a/ts/CI.ts
+++ b/ts/CI.ts
@@ -10,28 +10,30 @@ import type { IPCResponse as ChallengeResponseType } from './challenge';
 
 type ResolveType = (data: unknown) => void;
 
-export class CI {
-  private readonly eventListeners = new Map<string, Array<ResolveType>>();
+export type CIType = {
+  deviceName: string;
+  handleEvent: (event: string, data: unknown) => unknown;
+  setProvisioningURL: (url: string) => unknown;
+  solveChallenge: (response: ChallengeResponseType) => unknown;
+  waitForEvent: (event: string, timeout?: number) => unknown;
+};
 
-  private readonly completedEvents = new Map<string, Array<unknown>>();
+export function getCI(deviceName: string): CIType {
+  const eventListeners = new Map<string, Array<ResolveType>>();
+  const completedEvents = new Map<string, Array<unknown>>();
 
-  constructor(public readonly deviceName: string) {
-    ipcRenderer.on('ci:event', (_, event, data) => {
-      this.handleEvent(event, data);
-    });
-  }
+  ipcRenderer.on('ci:event', (_, event, data) => {
+    handleEvent(event, data);
+  });
 
-  public async waitForEvent(
-    event: string,
-    timeout = 60 * SECOND
-  ): Promise<unknown> {
-    const pendingCompleted = this.completedEvents.get(event) || [];
+  function waitForEvent(event: string, timeout = 60 * SECOND) {
+    const pendingCompleted = completedEvents.get(event) || [];
     const pending = pendingCompleted.shift();
     if (pending) {
       log.info(`CI: resolving pending result for ${event}`, pending);
 
       if (pendingCompleted.length === 0) {
-        this.completedEvents.delete(event);
+        completedEvents.delete(event);
       }
 
       return pending;
@@ -44,10 +46,10 @@ export class CI {
       reject(new Error('Timed out'));
     }, timeout);
 
-    let list = this.eventListeners.get(event);
+    let list = eventListeners.get(event);
     if (!list) {
       list = [];
-      this.eventListeners.set(event, list);
+      eventListeners.set(event, list);
     }
 
     list.push((value: unknown) => {
@@ -58,17 +60,17 @@ export class CI {
     return promise;
   }
 
-  public setProvisioningURL(url: string): void {
-    this.handleEvent('provisioning-url', url);
+  function setProvisioningURL(url: string): void {
+    handleEvent('provisioning-url', url);
   }
 
-  public handleEvent(event: string, data: unknown): void {
-    const list = this.eventListeners.get(event) || [];
+  function handleEvent(event: string, data: unknown): void {
+    const list = eventListeners.get(event) || [];
     const resolve = list.shift();
 
     if (resolve) {
       if (list.length === 0) {
-        this.eventListeners.delete(event);
+        eventListeners.delete(event);
       }
 
       log.info(`CI: got event ${event} with data`, data);
@@ -78,15 +80,23 @@ export class CI {
 
     log.info(`CI: postponing event ${event}`);
 
-    let resultList = this.completedEvents.get(event);
+    let resultList = completedEvents.get(event);
     if (!resultList) {
       resultList = [];
-      this.completedEvents.set(event, resultList);
+      completedEvents.set(event, resultList);
     }
     resultList.push(data);
   }
 
-  public solveChallenge(response: ChallengeResponseType): void {
+  function solveChallenge(response: ChallengeResponseType): void {
     window.Signal.challengeHandler?.onResponse(response);
   }
+
+  return {
+    deviceName,
+    handleEvent,
+    setProvisioningURL,
+    solveChallenge,
+    waitForEvent,
+  };
 }
diff --git a/ts/ConversationController.ts b/ts/ConversationController.ts
index dbeb61bf6c..3b04d5535e 100644
--- a/ts/ConversationController.ts
+++ b/ts/ConversationController.ts
@@ -194,13 +194,13 @@ export class ConversationController {
     drop(window.storage.put('unreadCount', newUnreadCount));
 
     if (newUnreadCount > 0) {
-      window.setBadgeCount(newUnreadCount);
+      window.IPC.setBadgeCount(newUnreadCount);
       window.document.title = `${window.getTitle()} (${newUnreadCount})`;
     } else {
-      window.setBadgeCount(0);
+      window.IPC.setBadgeCount(0);
       window.document.title = window.getTitle();
     }
-    window.updateTrayIcon(newUnreadCount);
+    window.IPC.updateTrayIcon(newUnreadCount);
   }
 
   onEmpty(): void {
diff --git a/ts/SignalProtocolStore.ts b/ts/SignalProtocolStore.ts
index b70e2f54f9..8e0f2237e0 100644
--- a/ts/SignalProtocolStore.ts
+++ b/ts/SignalProtocolStore.ts
@@ -2320,4 +2320,8 @@ export class SignalProtocolStore extends EventEmitter {
   }
 }
 
+export function getSignalProtocolStore(): SignalProtocolStore {
+  return new SignalProtocolStore();
+}
+
 window.SignalProtocolStore = SignalProtocolStore;
diff --git a/ts/WebAudioRecorder.ts b/ts/WebAudioRecorder.ts
new file mode 100644
index 0000000000..56cf902bed
--- /dev/null
+++ b/ts/WebAudioRecorder.ts
@@ -0,0 +1,161 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+const DEFAULT_OPTIONS = {
+  bufferSize: undefined, // buffer size (use browser default)
+  encodeAfterRecord: false,
+  mp3: {
+    mimeType: 'audio/mpeg',
+    bitRate: 160, // (CBR only): bit rate = [64 .. 320]
+  },
+  numChannels: 2, // number of channels
+  progressInterval: 1000, // encoding progress report interval (millisec)
+  timeLimit: 300, // recording time limit (sec)
+};
+
+type OptionsType = {
+  bufferSize: number | undefined;
+  numChannels: number;
+  timeLimit?: number;
+};
+
+export class WebAudioRecorder {
+  private buffer: Array<Float32Array>;
+  private options: OptionsType;
+  private context: BaseAudioContext;
+  private input: GainNode;
+  private onComplete: (recorder: WebAudioRecorder, blob: Blob) => unknown;
+  private onError: (recorder: WebAudioRecorder, error: string) => unknown;
+  private processor?: ScriptProcessorNode;
+  public worker?: Worker;
+
+  constructor(
+    sourceNode: GainNode,
+    options: Pick<OptionsType, 'timeLimit'>,
+    callbacks: {
+      onComplete: (recorder: WebAudioRecorder, blob: Blob) => unknown;
+      onError: (recorder: WebAudioRecorder, error: string) => unknown;
+    }
+  ) {
+    this.options = {
+      ...DEFAULT_OPTIONS,
+      ...options,
+    };
+
+    this.context = sourceNode.context;
+    this.input = this.context.createGain();
+    sourceNode.connect(this.input);
+    this.buffer = [];
+    this.initWorker();
+
+    this.onComplete = callbacks.onComplete;
+    this.onError = callbacks.onError;
+  }
+
+  isRecording(): boolean {
+    return this.processor != null;
+  }
+
+  startRecording(): void {
+    if (this.isRecording()) {
+      this.error('startRecording: previous recording is running');
+      return;
+    }
+
+    const { buffer, worker } = this;
+    const { bufferSize, numChannels } = this.options;
+
+    if (!worker) {
+      this.error('startRecording: worker not initialized');
+      return;
+    }
+
+    this.processor = this.context.createScriptProcessor(
+      bufferSize,
+      numChannels,
+      numChannels
+    );
+    this.input.connect(this.processor);
+    this.processor.connect(this.context.destination);
+    this.processor.onaudioprocess = event => {
+      // eslint-disable-next-line no-plusplus
+      for (let ch = 0; ch < numChannels; ++ch) {
+        buffer[ch] = event.inputBuffer.getChannelData(ch);
+      }
+      worker.postMessage({ command: 'record', buffer });
+    };
+    worker.postMessage({
+      command: 'start',
+      bufferSize: this.processor.bufferSize,
+    });
+  }
+
+  cancelRecording(): void {
+    if (!this.isRecording()) {
+      this.error('cancelRecording: no recording is running');
+      return;
+    }
+
+    if (!this.worker || !this.processor) {
+      this.error('startRecording: worker not initialized');
+      return;
+    }
+
+    this.input.disconnect();
+    this.processor.disconnect();
+    delete this.processor;
+    this.worker.postMessage({ command: 'cancel' });
+  }
+
+  finishRecording(): void {
+    if (!this.isRecording()) {
+      this.error('finishRecording: no recording is running');
+      return;
+    }
+
+    if (!this.worker || !this.processor) {
+      this.error('startRecording: worker not initialized');
+      return;
+    }
+
+    this.input.disconnect();
+    this.processor.disconnect();
+    delete this.processor;
+    this.worker.postMessage({ command: 'finish' });
+  }
+
+  private initWorker(): void {
+    if (this.worker != null) {
+      this.worker.terminate();
+    }
+
+    this.worker = new Worker('js/WebAudioRecorderMp3.js');
+    this.worker.onmessage = event => {
+      const { data } = event;
+      switch (data.command) {
+        case 'complete':
+          this.onComplete(this, data.blob);
+          break;
+        case 'error':
+          this.error(data.message);
+          break;
+        default:
+          break;
+      }
+    };
+    this.worker.postMessage({
+      command: 'init',
+      config: {
+        sampleRate: this.context.sampleRate,
+        numChannels: this.options.numChannels,
+      },
+      options: this.options,
+    });
+  }
+
+  error(message: string): void {
+    this.onError(this, `WebAudioRecorder.js: ${message}`);
+  }
+}
+
+window.WebAudioRecorder = WebAudioRecorder;
diff --git a/ts/background.ts b/ts/background.ts
index 672c909e70..965d20b686 100644
--- a/ts/background.ts
+++ b/ts/background.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import { webFrame } from 'electron';
-import { isNumber, clone, debounce } from 'lodash';
+import { isNumber, debounce } from 'lodash';
 import { bindActionCreators } from 'redux';
 import { render } from 'react-dom';
 import { batch as batchDispatch } from 'react-redux';
@@ -56,7 +56,7 @@ import { GROUP_CREDENTIALS_KEY } from './services/groupCredentialFetcher';
 import * as KeyboardLayout from './services/keyboardLayout';
 import * as StorageService from './services/storage';
 import { RoutineProfileRefresher } from './routineProfileRefresh';
-import { isMoreRecentThan, isOlderThan, toDayMillis } from './util/timestamp';
+import { isOlderThan, toDayMillis } from './util/timestamp';
 import { isValidReactionEmoji } from './reactions/isValidReactionEmoji';
 import type { ConversationModel } from './models/conversations';
 import { getContact, isIncoming } from './messages/helpers';
@@ -161,10 +161,11 @@ import { clearConversationDraftAttachments } from './util/clearConversationDraft
 import { removeLinkPreview } from './services/LinkPreview';
 import { PanelType } from './types/Panels';
 import { getQuotedMessageSelector } from './state/selectors/composer';
+import { flushAttachmentDownloadQueue } from './util/attachmentDownloadQueue';
+import { StartupQueue } from './util/StartupQueue';
+import { showConfirmationDialog } from './util/showConfirmationDialog';
 import { onCallEventSync } from './util/onCallEventSync';
 
-const MAX_ATTACHMENT_DOWNLOAD_AGE = 3600 * 72 * 1000;
-
 export function isOverHourIntoPast(timestamp: number): boolean {
   const HOUR = 1000 * 60 * 60;
   return isNumber(timestamp) && isOlderThan(timestamp, HOUR);
@@ -201,15 +202,11 @@ export async function startApp(): Promise<void> {
 
   await KeyboardLayout.initialize();
 
-  window.Whisper.events = clone(window.Backbone.Events);
-  window.Signal.Util.MessageController.install();
-  window.Signal.conversationControllerStart();
-  window.startupProcessingQueue = new window.Signal.Util.StartupQueue();
+  StartupQueue.initialize();
   notificationService.initialize({
     i18n: window.i18n,
     storage: window.storage,
   });
-  window.attachmentDownloadQueue = [];
 
   await window.Signal.Util.initializeMessageCounter();
 
@@ -249,8 +246,8 @@ export async function startApp(): Promise<void> {
       },
 
       requestChallenge(request) {
-        if (window.CI) {
-          window.CI.handleEvent('challenge', request);
+        if (window.Signal.CI) {
+          window.Signal.CI.handleEvent('challenge', request);
           return;
         }
         window.sendChallengeRequest(request);
@@ -494,7 +491,7 @@ export async function startApp(): Promise<void> {
     window.addEventListener('dblclick', (event: Event) => {
       const target = event.target as HTMLElement;
       if (isWindowDragElement(target)) {
-        window.titleBarDoubleClick();
+        window.IPC.titleBarDoubleClick();
       }
     });
   }
@@ -529,7 +526,7 @@ export async function startApp(): Promise<void> {
     }
   }
 
-  const builtInImages = await window.getBuiltInImages();
+  const builtInImages = await window.IPC.getBuiltInImages();
   preload(builtInImages);
 
   // We add this to window here because the default Node context is erased at the end
@@ -608,7 +605,7 @@ export async function startApp(): Promise<void> {
 
         try {
           await new Promise<void>((resolve, reject) => {
-            window.showConfirmationDialog({
+            showConfirmationDialog({
               dialogName: 'deleteOldIndexedDBData',
               onTopOfEverything: true,
               cancelText: window.i18n('quit'),
@@ -624,7 +621,7 @@ export async function startApp(): Promise<void> {
             'User chose not to delete old data. Shutting down.',
             Errors.toLogFormat(error)
           );
-          window.shutdown();
+          window.IPC.shutdown();
           return;
         }
 
@@ -852,7 +849,7 @@ export async function startApp(): Promise<void> {
       // This one should always be last - it could restart the app
       if (window.isBeforeVersion(lastVersion, 'v5.30.0-alpha')) {
         await deleteAllLogs();
-        window.restart();
+        window.IPC.restart();
         return;
       }
     }
@@ -1253,22 +1250,6 @@ export async function startApp(): Promise<void> {
       }
     });
 
-    window.Whisper.events.on(
-      'setWindowStats',
-      ({
-        isFullScreen,
-        isMaximized,
-      }: {
-        isFullScreen: boolean;
-        isMaximized: boolean;
-      }) => {
-        window.reduxActions.user.userChanged({
-          isMainWindowMaximized: isMaximized,
-          isMainWindowFullScreen: isFullScreen,
-        });
-      }
-    );
-
     window.Whisper.events.on('setMenuOptions', (options: MenuOptionsType) => {
       window.reduxActions.user.userChanged({ menuOptions: options });
     });
@@ -1677,7 +1658,7 @@ export async function startApp(): Promise<void> {
           event.preventDefault();
           event.stopPropagation();
 
-          window.showConfirmationDialog({
+          showConfirmationDialog({
             dialogName: 'deleteMessage',
             confirmStyle: 'negative',
             message: window.i18n('deleteWarning'),
@@ -1895,8 +1876,8 @@ export async function startApp(): Promise<void> {
       document.getElementById('app-container')
     );
     const hideMenuBar = window.storage.get('hide-menu-bar', false);
-    window.setAutoHideMenuBar(hideMenuBar);
-    window.setMenuBarVisibility(!hideMenuBar);
+    window.IPC.setAutoHideMenuBar(hideMenuBar);
+    window.IPC.setMenuBarVisibility(!hideMenuBar);
 
     startTimeTravelDetector(() => {
       window.Whisper.events.trigger('timetravel');
@@ -1927,7 +1908,7 @@ export async function startApp(): Promise<void> {
     window.addEventListener('unload', () => notificationService.fastClear());
 
     notificationService.on('click', (id, messageId, storyId) => {
-      window.showWindow();
+      window.IPC.showWindow();
 
       if (id) {
         if (storyId) {
@@ -2491,7 +2472,7 @@ export async function startApp(): Promise<void> {
       window.flushAllWaitBatchers(),
     ]);
     log.info('onEmpty: All outstanding database requests complete');
-    window.readyForUpdates();
+    window.IPC.readyForUpdates();
     window.ConversationController.onEmpty();
 
     // Start listeners here, after we get through our queue.
@@ -2512,7 +2493,7 @@ export async function startApp(): Promise<void> {
     window.reduxActions.app.initialLoadComplete();
 
     const processedCount = messageReceiver?.getAndResetProcessedCount() || 0;
-    window.logAppLoadedEvent?.({
+    window.IPC.logAppLoadedEvent?.({
       processedCount,
     });
     if (messageReceiver) {
@@ -2520,53 +2501,12 @@ export async function startApp(): Promise<void> {
     }
 
     window.Signal.Util.setBatchingStrategy(false);
-
-    const attachmentDownloadQueue = window.attachmentDownloadQueue || [];
-
-    // NOTE: ts/models/messages.ts expects this global to become undefined
-    // once we stop processing the queue.
-    window.attachmentDownloadQueue = undefined;
-
-    const MAX_ATTACHMENT_MSGS_TO_DOWNLOAD = 250;
-    const attachmentsToDownload = attachmentDownloadQueue.filter(
-      (message, index) =>
-        index <= MAX_ATTACHMENT_MSGS_TO_DOWNLOAD ||
-        isMoreRecentThan(
-          message.getReceivedAt(),
-          MAX_ATTACHMENT_DOWNLOAD_AGE
-        ) ||
-        // Stickers and long text attachments has to be downloaded for UI
-        // to display the message properly.
-        message.hasRequiredAttachmentDownloads()
-    );
-    log.info(
-      'Downloading recent attachments of total attachments',
-      attachmentsToDownload.length,
-      attachmentDownloadQueue.length
-    );
-
-    if (window.startupProcessingQueue) {
-      window.startupProcessingQueue.flush();
-      window.startupProcessingQueue = undefined;
-    }
-
-    const messagesWithDownloads = await Promise.all(
-      attachmentsToDownload.map(message => message.queueAttachmentDownloads())
-    );
-    const messagesToSave: Array<MessageAttributesType> = [];
-    messagesWithDownloads.forEach((shouldSave, messageKey) => {
-      if (shouldSave) {
-        const message = attachmentsToDownload[messageKey];
-        messagesToSave.push(message.attributes);
-      }
-    });
-    await window.Signal.Data.saveMessages(messagesToSave, {
-      ourUuid: storage.user.getCheckedUuid().toString(),
-    });
+    StartupQueue.flush();
+    await flushAttachmentDownloadQueue();
 
     // Process crash reports if any
     window.reduxActions.crashReports.setCrashReportCount(
-      await window.crashReports.getCount()
+      await window.IPC.crashReports.getCount()
     );
 
     // Kick off a profile refresh if necessary, but don't wait for it, as failure is
diff --git a/ts/components/App.tsx b/ts/components/App.tsx
index ad4f0eba06..259b0ab838 100644
--- a/ts/components/App.tsx
+++ b/ts/components/App.tsx
@@ -43,6 +43,7 @@ type PropsType = {
   onUndoArchive: (conversationId: string) => unknown;
   openFileInFolder: (target: string) => unknown;
   hasCustomTitleBar: boolean;
+  osClassName: string;
   hideMenuBar: boolean;
 
   executeMenuRole: ExecuteMenuRoleType;
@@ -75,6 +76,7 @@ export function App({
   onUndoArchive,
   openFileInFolder,
   openInbox,
+  osClassName,
   registerSingleDevice,
   renderCallManager,
   renderGlobalModalContainer,
@@ -95,7 +97,7 @@ export function App({
     contents = <SmartInstallScreen />;
   } else if (appView === AppViewType.Standalone) {
     const onComplete = () => {
-      window.removeSetupMenuItems();
+      window.IPC.removeSetupMenuItems();
       openInbox();
     };
     contents = (
@@ -123,6 +125,19 @@ export function App({
     }
   }, [theme]);
 
+  useEffect(() => {
+    document.body.classList.add(osClassName);
+  }, [osClassName]);
+
+  useEffect(() => {
+    document.body.classList.toggle('os-has-custom-titlebar', hasCustomTitleBar);
+  }, [hasCustomTitleBar]);
+
+  useEffect(() => {
+    document.body.classList.toggle('full-screen', isFullScreen);
+    document.body.classList.toggle('maximized', isMaximized);
+  }, [isFullScreen, isMaximized]);
+
   const isPageVisible = usePageVisibility();
   useEffect(() => {
     document.body.classList.toggle('page-is-visible', isPageVisible);
diff --git a/ts/components/CompositionInput.tsx b/ts/components/CompositionInput.tsx
index 9d1ccefd43..15844f7058 100644
--- a/ts/components/CompositionInput.tsx
+++ b/ts/components/CompositionInput.tsx
@@ -668,7 +668,11 @@ export function CompositionInput(props: Props): React.ReactElement {
     <Manager>
       <Reference>
         {({ ref }) => (
-          <div className={getClassName('__input')} ref={ref}>
+          <div
+            className={getClassName('__input')}
+            ref={ref}
+            data-testid="CompositionInput"
+          >
             {children}
             <div
               ref={
diff --git a/ts/components/ConversationList.tsx b/ts/components/ConversationList.tsx
index 932696f5b5..f2c0cb44a7 100644
--- a/ts/components/ConversationList.tsx
+++ b/ts/components/ConversationList.tsx
@@ -321,6 +321,7 @@ export function ConversationList({
             'badges',
             'color',
             'draftPreview',
+            'groupId',
             'id',
             'isMe',
             'isSelected',
diff --git a/ts/components/StandaloneRegistration.tsx b/ts/components/StandaloneRegistration.tsx
index 2509fe3bde..a9adb98068 100644
--- a/ts/components/StandaloneRegistration.tsx
+++ b/ts/components/StandaloneRegistration.tsx
@@ -106,7 +106,7 @@ export function StandaloneRegistration({
   registerSingleDevice: (number: string, code: string) => Promise<void>;
 }): JSX.Element {
   useEffect(() => {
-    window.readyForUpdates();
+    window.IPC.readyForUpdates();
   }, []);
 
   const [isValidNumber, setIsValidNumber] = useState(false);
diff --git a/ts/components/ToastManager.tsx b/ts/components/ToastManager.tsx
index ad773907fb..b307fa529f 100644
--- a/ts/components/ToastManager.tsx
+++ b/ts/components/ToastManager.tsx
@@ -162,7 +162,7 @@ export function ToastManager({
         onClose={hideToast}
         toastAction={{
           label: i18n('Toast--error--action'),
-          onClick: () => window.showDebugLog(),
+          onClick: () => window.IPC.showDebugLog(),
         }}
       >
         {i18n('Toast--error')}
diff --git a/ts/components/conversation/GIF.tsx b/ts/components/conversation/GIF.tsx
index 5de53e0e0a..c8c444550e 100644
--- a/ts/components/conversation/GIF.tsx
+++ b/ts/components/conversation/GIF.tsx
@@ -16,6 +16,7 @@ import {
 } from '../../types/Attachment';
 import * as Errors from '../../types/errors';
 import * as log from '../../logging/log';
+import { useReducedMotion } from '../../hooks/useReducedMotion';
 
 const MAX_GIF_REPEAT = 4;
 const MAX_GIF_TIME = 8;
@@ -28,8 +29,6 @@ export type Props = {
   readonly i18n: LocalizerType;
   readonly theme?: ThemeType;
 
-  readonly reducedMotion?: boolean;
-
   onError(): void;
   showVisualAttachment(): void;
   kickOffAttachmentDownload(): void;
@@ -46,16 +45,12 @@ export function GIF(props: Props): JSX.Element {
     i18n,
     theme,
 
-    reducedMotion = Boolean(
-      window.Accessibility && window.Accessibility.reducedMotionSetting
-    ),
-
     onError,
     showVisualAttachment,
     kickOffAttachmentDownload,
   } = props;
 
-  const tapToPlay = reducedMotion;
+  const tapToPlay = useReducedMotion();
 
   const videoRef = useRef<HTMLVideoElement | null>(null);
   const { height, width } = getImageDimensions(attachment, size);
diff --git a/ts/components/conversation/Message.tsx b/ts/components/conversation/Message.tsx
index c07badea8b..bac590f7a9 100644
--- a/ts/components/conversation/Message.tsx
+++ b/ts/components/conversation/Message.tsx
@@ -221,7 +221,6 @@ export type PropsData = {
     | 'title'
     | 'unblurredAvatarPath'
   >;
-  reducedMotion?: boolean;
   conversationType: ConversationTypeType;
   attachments?: ReadonlyArray<AttachmentType>;
   giftBadge?: GiftBadgeType;
@@ -521,7 +520,7 @@ export class Message extends React.PureComponent<Props, State> {
         status === 'viewed')
     ) {
       const delta = Date.now() - timestamp;
-      window.CI?.handleEvent('message:send-complete', {
+      window.Signal.CI?.handleEvent('message:send-complete', {
         timestamp,
         delta,
       });
@@ -838,7 +837,6 @@ export class Message extends React.PureComponent<Props, State> {
       pushPanelForConversation,
       quote,
       readStatus,
-      reducedMotion,
       renderAudioAttachment,
       renderingContext,
       shouldCollapseAbove,
@@ -889,7 +887,6 @@ export class Message extends React.PureComponent<Props, State> {
               theme={theme}
               i18n={i18n}
               tabIndex={0}
-              reducedMotion={reducedMotion}
               onError={this.handleImageError}
               showVisualAttachment={() => {
                 showLightbox({
@@ -2529,10 +2526,11 @@ export class Message extends React.PureComponent<Props, State> {
       attachments,
       direction,
       isSticker,
+      onKeyDown,
+      renderMenu,
       shouldCollapseAbove,
       shouldCollapseBelow,
-      renderMenu,
-      onKeyDown,
+      timestamp,
     } = this.props;
     const { expired, expiring, isSelected, imageBroken } = this.state;
 
@@ -2554,6 +2552,7 @@ export class Message extends React.PureComponent<Props, State> {
           isSelected ? 'module-message--selected' : null,
           expiring ? 'module-message--expired' : null
         )}
+        data-testid={timestamp}
         tabIndex={0}
         // We need to have a role because screenreaders need to be able to focus here to
         //   read the message, but we can't be a button; that would break inner buttons.
diff --git a/ts/components/conversation/Timeline.tsx b/ts/components/conversation/Timeline.tsx
index 8041b4f776..4144e2775c 100644
--- a/ts/components/conversation/Timeline.tsx
+++ b/ts/components/conversation/Timeline.tsx
@@ -1147,5 +1147,5 @@ function getRowIndexFromElement(
 }
 
 function showDebugLog() {
-  window.showDebugLog();
+  window.IPC.showDebugLog();
 }
diff --git a/ts/components/conversation/TimelineMessage.stories.tsx b/ts/components/conversation/TimelineMessage.stories.tsx
index f33b596689..12b852439b 100644
--- a/ts/components/conversation/TimelineMessage.stories.tsx
+++ b/ts/components/conversation/TimelineMessage.stories.tsx
@@ -224,7 +224,6 @@ const renderAudioAttachment: Props['renderAudioAttachment'] = props => (
 const createProps = (overrideProps: Partial<Props> = {}): Props => ({
   attachments: overrideProps.attachments,
   author: overrideProps.author || getDefaultConversation(),
-  reducedMotion: boolean('reducedMotion', false),
   bodyRanges: overrideProps.bodyRanges,
   canReact: true,
   canReply: true,
diff --git a/ts/components/conversation/conversation-details/ConversationDetailsHeader.tsx b/ts/components/conversation/conversation-details/ConversationDetailsHeader.tsx
index e224e94a11..337208c6b6 100644
--- a/ts/components/conversation/conversation-details/ConversationDetailsHeader.tsx
+++ b/ts/components/conversation/conversation-details/ConversationDetailsHeader.tsx
@@ -148,7 +148,7 @@ export function ConversationDetailsHeader({
 
   if (canEdit) {
     return (
-      <div className={bem('root')}>
+      <div className={bem('root')} data-testid="ConversationDetailsHeader">
         {modal}
         {avatar}
         <button
@@ -182,7 +182,7 @@ export function ConversationDetailsHeader({
   }
 
   return (
-    <div className={bem('root')}>
+    <div className={bem('root')} data-testid="ConversationDetailsHeader">
       {modal}
       {avatar}
       {contents}
diff --git a/ts/components/conversationList/BaseConversationListItem.tsx b/ts/components/conversationList/BaseConversationListItem.tsx
index f703211136..9ab75160fb 100644
--- a/ts/components/conversationList/BaseConversationListItem.tsx
+++ b/ts/components/conversationList/BaseConversationListItem.tsx
@@ -5,7 +5,6 @@ import type { ReactNode, FunctionComponent } from 'react';
 import React, { useCallback, useEffect, useMemo, useState } from 'react';
 import classNames from 'classnames';
 import { isBoolean, isNumber } from 'lodash';
-import { v4 as uuid } from 'uuid';
 
 import { Avatar, AvatarSize } from '../Avatar';
 import type { BadgeType } from '../../badges/types';
@@ -17,6 +16,7 @@ import { Spinner } from '../Spinner';
 import { Time } from '../Time';
 import { formatDateTimeShort } from '../../util/timestamp';
 import * as durations from '../../util/durations';
+import { UUID } from '../../types/UUID';
 
 const BASE_CLASS_NAME =
   'module-conversation-list__item--contact-or-conversation';
@@ -52,11 +52,13 @@ type PropsType = {
   shouldShowSpinner?: boolean;
   unreadCount?: number;
   avatarSize?: AvatarSize;
+  testId?: string;
 } & Pick<
   ConversationType,
   | 'acceptedMessageRequest'
   | 'avatarPath'
   | 'color'
+  | 'groupId'
   | 'isMe'
   | 'markedUnread'
   | 'phoneNumber'
@@ -64,6 +66,7 @@ type PropsType = {
   | 'sharedGroupNames'
   | 'title'
   | 'unblurredAvatarPath'
+  | 'uuid'
 > &
   (
     | { badge?: undefined; theme?: ThemeType }
@@ -80,6 +83,7 @@ export const BaseConversationListItem: FunctionComponent<PropsType> =
       color,
       conversationType,
       disabled,
+      groupId,
       headerDate,
       headerName,
       i18n,
@@ -97,13 +101,16 @@ export const BaseConversationListItem: FunctionComponent<PropsType> =
       profileName,
       sharedGroupNames,
       shouldShowSpinner,
+      testId: overrideTestId,
       title,
       unblurredAvatarPath,
       unreadCount,
+      uuid,
     } = props;
 
     const identifier = id ? cleanId(id) : undefined;
-    const htmlId = useMemo(() => uuid(), []);
+    const htmlId = useMemo(() => UUID.generate().toString(), []);
+    const testId = overrideTestId || groupId || uuid;
     const isUnread = isConversationUnread({ markedUnread, unreadCount });
 
     const isAvatarNoteToSelf = isBoolean(isNoteToSelf)
@@ -222,6 +229,7 @@ export const BaseConversationListItem: FunctionComponent<PropsType> =
             { [`${BASE_CLASS_NAME}--is-checkbox--disabled`]: disabled }
           )}
           data-id={identifier}
+          data-testid={testId}
           htmlFor={htmlId}
           // `onClick` is will double-fire if we're enabled. We want it to fire when we're
           //   disabled so we can show any "can't add contact" modals, etc. This won't
@@ -242,6 +250,7 @@ export const BaseConversationListItem: FunctionComponent<PropsType> =
             `${BASE_CLASS_NAME}--is-button`
           )}
           data-id={identifier}
+          data-testid={testId}
           disabled={disabled}
           onClick={onClick}
           type="button"
@@ -252,7 +261,11 @@ export const BaseConversationListItem: FunctionComponent<PropsType> =
     }
 
     return (
-      <div className={commonClassNames} data-id={identifier}>
+      <div
+        className={commonClassNames}
+        data-id={identifier}
+        data-testid={testId}
+      >
         {contents}
       </div>
     );
diff --git a/ts/components/conversationList/ContactCheckbox.tsx b/ts/components/conversationList/ContactCheckbox.tsx
index ead1eba8c8..2e59e9adf5 100644
--- a/ts/components/conversationList/ContactCheckbox.tsx
+++ b/ts/components/conversationList/ContactCheckbox.tsx
@@ -30,6 +30,7 @@ export type PropsDataType = {
   | 'acceptedMessageRequest'
   | 'avatarPath'
   | 'color'
+  | 'groupId'
   | 'id'
   | 'isMe'
   | 'phoneNumber'
@@ -38,6 +39,7 @@ export type PropsDataType = {
   | 'title'
   | 'type'
   | 'unblurredAvatarPath'
+  | 'uuid'
 >;
 
 type PropsHousekeepingType = {
@@ -59,6 +61,7 @@ export const ContactCheckbox: FunctionComponent<PropsType> = React.memo(
     badge,
     color,
     disabledReason,
+    groupId,
     i18n,
     id,
     isChecked,
@@ -71,6 +74,7 @@ export const ContactCheckbox: FunctionComponent<PropsType> = React.memo(
     title,
     type,
     unblurredAvatarPath,
+    uuid,
   }) {
     const disabled = Boolean(disabledReason);
 
@@ -104,6 +108,7 @@ export const ContactCheckbox: FunctionComponent<PropsType> = React.memo(
         color={color}
         conversationType={type}
         disabled={disabled}
+        groupId={groupId}
         headerName={headerName}
         i18n={i18n}
         id={id}
@@ -117,6 +122,7 @@ export const ContactCheckbox: FunctionComponent<PropsType> = React.memo(
         theme={theme}
         title={title}
         unblurredAvatarPath={unblurredAvatarPath}
+        uuid={uuid}
       />
     );
   }
diff --git a/ts/components/conversationList/ContactListItem.tsx b/ts/components/conversationList/ContactListItem.tsx
index 6e7a05db16..fdc2d0dc26 100644
--- a/ts/components/conversationList/ContactListItem.tsx
+++ b/ts/components/conversationList/ContactListItem.tsx
@@ -22,6 +22,7 @@ export type ContactListItemConversationType = Pick<
   | 'avatarPath'
   | 'badges'
   | 'color'
+  | 'groupId'
   | 'id'
   | 'isMe'
   | 'phoneNumber'
@@ -54,6 +55,7 @@ export const ContactListItem: FunctionComponent<PropsType> = React.memo(
     avatarPath,
     badge,
     color,
+    groupId,
     i18n,
     id,
     isMe,
@@ -89,6 +91,7 @@ export const ContactListItem: FunctionComponent<PropsType> = React.memo(
         badge={badge}
         color={color}
         conversationType={type}
+        groupId={groupId}
         headerName={headerName}
         i18n={i18n}
         id={id}
@@ -102,6 +105,7 @@ export const ContactListItem: FunctionComponent<PropsType> = React.memo(
         theme={theme}
         title={title}
         unblurredAvatarPath={unblurredAvatarPath}
+        uuid={uuid}
       />
     );
   }
diff --git a/ts/components/conversationList/ConversationListItem.tsx b/ts/components/conversationList/ConversationListItem.tsx
index 197ee33c64..18ac38fb89 100644
--- a/ts/components/conversationList/ConversationListItem.tsx
+++ b/ts/components/conversationList/ConversationListItem.tsx
@@ -41,6 +41,7 @@ export type PropsData = Pick<
   | 'badges'
   | 'color'
   | 'draftPreview'
+  | 'groupId'
   | 'id'
   | 'isMe'
   // NOTE: Passed for CI, not used for rendering
@@ -79,6 +80,7 @@ export const ConversationListItem: FunctionComponent<Props> = React.memo(
     badge,
     color,
     draftPreview,
+    groupId,
     i18n,
     id,
     isMe,
@@ -180,6 +182,7 @@ export const ConversationListItem: FunctionComponent<Props> = React.memo(
         badge={badge}
         color={color}
         conversationType={type}
+        groupId={groupId}
         headerDate={lastUpdated}
         headerName={headerName}
         i18n={i18n}
@@ -198,6 +201,7 @@ export const ConversationListItem: FunctionComponent<Props> = React.memo(
         title={title}
         unreadCount={unreadCount}
         unblurredAvatarPath={unblurredAvatarPath}
+        uuid={uuid}
       />
     );
   }
diff --git a/ts/components/conversationList/CreateNewGroupButton.tsx b/ts/components/conversationList/CreateNewGroupButton.tsx
index c8524d4c38..668ffe0904 100644
--- a/ts/components/conversationList/CreateNewGroupButton.tsx
+++ b/ts/components/conversationList/CreateNewGroupButton.tsx
@@ -26,6 +26,7 @@ export const CreateNewGroupButton: FunctionComponent<PropsType> = React.memo(
         isSelected={false}
         onClick={onClick}
         sharedGroupNames={[]}
+        testId="CreateNewGroupButton"
         title={title}
       />
     );
diff --git a/ts/components/stickers/StickerManager.tsx b/ts/components/stickers/StickerManager.tsx
index f563295d16..2c2af487b4 100644
--- a/ts/components/stickers/StickerManager.tsx
+++ b/ts/components/stickers/StickerManager.tsx
@@ -82,7 +82,12 @@ export const StickerManager = React.memo(function StickerManagerInner({
           uninstallStickerPack={uninstallStickerPack}
         />
       ) : null}
-      <div className="module-sticker-manager" tabIndex={-1} ref={focusRef}>
+      <div
+        className="module-sticker-manager"
+        data-testid="StickerManager"
+        tabIndex={-1}
+        ref={focusRef}
+      >
         <Tabs
           initialSelectedTab={TabViews.Available}
           tabs={[
diff --git a/ts/components/stickers/StickerManagerPackRow.tsx b/ts/components/stickers/StickerManagerPackRow.tsx
index 2350a687eb..f998199551 100644
--- a/ts/components/stickers/StickerManagerPackRow.tsx
+++ b/ts/components/stickers/StickerManagerPackRow.tsx
@@ -113,6 +113,7 @@ export const StickerManagerPackRow = React.memo(
           onKeyDown={handleKeyDown}
           onClick={handleClickPreview}
           className="module-sticker-manager__pack-row"
+          data-testid={id}
         >
           {pack.cover ? (
             <img
diff --git a/ts/groups.ts b/ts/groups.ts
index 3a18996a56..a73b500e38 100644
--- a/ts/groups.ts
+++ b/ts/groups.ts
@@ -2137,7 +2137,10 @@ export async function getGroupMigrationMembers(
             `getGroupMigrationMembers/${logId}: membersV2 - missing local contact for ${e164}, skipping.`
           );
         }
-        if (!isMe(contact.attributes) && window.GV2_MIGRATION_DISABLE_ADD) {
+        if (
+          !isMe(contact.attributes) &&
+          window.Flags.GV2_MIGRATION_DISABLE_ADD
+        ) {
           log.warn(
             `getGroupMigrationMembers/${logId}: membersV2 - skipping ${e164} due to GV2_MIGRATION_DISABLE_ADD flag`
           );
@@ -2205,7 +2208,10 @@ export async function getGroupMigrationMembers(
         return null;
       }
 
-      if (!isMe(contact.attributes) && window.GV2_MIGRATION_DISABLE_INVITE) {
+      if (
+        !isMe(contact.attributes) &&
+        window.Flags.GV2_MIGRATION_DISABLE_INVITE
+      ) {
         log.warn(
           `getGroupMigrationMembers/${logId}: pendingMembersV2 - skipping ${e164} due to GV2_MIGRATION_DISABLE_INVITE flag`
         );
@@ -3402,7 +3408,7 @@ async function getGroupUpdates({
     newRevision === currentRevision + 1;
 
   if (
-    window.GV2_ENABLE_SINGLE_CHANGE_PROCESSING &&
+    window.Flags.GV2_ENABLE_SINGLE_CHANGE_PROCESSING &&
     wrappedGroupChange &&
     isNumber(newRevision) &&
     (isInitialCreationMessage || weAreAwaitingApproval || isOneVersionUp)
@@ -3455,7 +3461,7 @@ async function getGroupUpdates({
 
   if (
     (!isFirstFetch || isNumber(newRevision)) &&
-    window.GV2_ENABLE_CHANGE_PROCESSING
+    window.Flags.GV2_ENABLE_CHANGE_PROCESSING
   ) {
     try {
       return await updateGroupViaLogs({
@@ -3483,7 +3489,7 @@ async function getGroupUpdates({
     }
   }
 
-  if (window.GV2_ENABLE_STATE_PROCESSING) {
+  if (window.Flags.GV2_ENABLE_STATE_PROCESSING) {
     try {
       return await updateGroupViaState({
         dropInitialJoinMessage,
@@ -3506,7 +3512,7 @@ async function getGroupUpdates({
     }
   }
 
-  if (window.GV2_ENABLE_PRE_JOIN_FETCH) {
+  if (window.Flags.GV2_ENABLE_PRE_JOIN_FETCH) {
     try {
       return await updateGroupViaPreJoinInfo({
         group,
diff --git a/ts/manage_full_screen_class.ts b/ts/manage_full_screen_class.ts
deleted file mode 100644
index 5c3c7a217d..0000000000
--- a/ts/manage_full_screen_class.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2021 Signal Messenger, LLC
-// SPDX-License-Identifier: AGPL-3.0-only
-
-{
-  const updateFullScreenClass = (
-    isFullScreen: boolean,
-    isMaximized: boolean
-  ) => {
-    document.body.classList.toggle('full-screen', isFullScreen);
-    document.body.classList.toggle('maximized', isMaximized);
-  };
-  updateFullScreenClass(window.isFullScreen(), window.isMaximized());
-  window.onFullScreenChange = updateFullScreenClass;
-}
diff --git a/ts/messageModifiers/MessageReceipts.ts b/ts/messageModifiers/MessageReceipts.ts
index 2434718626..8b33b8ad9d 100644
--- a/ts/messageModifiers/MessageReceipts.ts
+++ b/ts/messageModifiers/MessageReceipts.ts
@@ -266,7 +266,9 @@ export class MessageReceipts extends Collection<MessageReceiptModel> {
 
           // We want the above call to not be delayed when testing with
           // CI.
-          window.CI ? deleteSentProtoBatcher.flushAndWait() : Promise.resolve(),
+          window.Signal.CI
+            ? deleteSentProtoBatcher.flushAndWait()
+            : Promise.resolve(),
         ]);
       } else {
         log.warn(
diff --git a/ts/messageModifiers/ReadSyncs.ts b/ts/messageModifiers/ReadSyncs.ts
index f95ab938e3..cd3617ca28 100644
--- a/ts/messageModifiers/ReadSyncs.ts
+++ b/ts/messageModifiers/ReadSyncs.ts
@@ -11,6 +11,7 @@ import { isMessageUnread } from '../util/isMessageUnread';
 import { notificationService } from '../services/notifications';
 import * as log from '../logging/log';
 import * as Errors from '../types/errors';
+import { StartupQueue } from '../util/StartupQueue';
 
 export type ReadSyncAttributesType = {
   senderId: string;
@@ -119,10 +120,10 @@ export class ReadSyncs extends Collection {
           void message.getConversation()?.onReadMessage(message, readAt);
         };
 
-        if (window.startupProcessingQueue) {
+        if (StartupQueue.isReady()) {
           const conversation = message.getConversation();
           if (conversation) {
-            window.startupProcessingQueue.add(
+            StartupQueue.add(
               conversation.get('id'),
               message.get('sent_at'),
               updateConversation
diff --git a/ts/models/conversations.ts b/ts/models/conversations.ts
index c1c2d1bb54..caf254818f 100644
--- a/ts/models/conversations.ts
+++ b/ts/models/conversations.ts
@@ -158,6 +158,7 @@ import { isSignalConversation } from '../util/isSignalConversation';
 import { isMemberRequestingToJoin } from '../util/isMemberRequestingToJoin';
 import { removePendingMember } from '../util/removePendingMember';
 import { isMemberPending } from '../util/isMemberPending';
+import { imageToBlurHash } from '../util/imageToBlurHash';
 
 const EMPTY_ARRAY: Readonly<[]> = [];
 const EMPTY_GROUP_COLLISIONS: GroupNameCollisionsWithIdsByTitle = {};
@@ -3890,7 +3891,7 @@ export class ConversationModel extends window.Backbone
         contentType,
         width,
         height,
-        blurHash: await window.imageToBlurHash(
+        blurHash: await imageToBlurHash(
           new Blob([data], {
             type: IMAGE_JPEG,
           })
@@ -5527,7 +5528,7 @@ export class ConversationModel extends window.Backbone
     const delta = now - startedAt;
 
     log.info(`conversation ${this.idForLogging()} open took ${delta}ms`);
-    window.CI?.handleEvent('conversation:open', { delta });
+    window.Signal.CI?.handleEvent('conversation:open', { delta });
   }
 
   async flushDebouncedUpdates(): Promise<void> {
diff --git a/ts/models/messages.ts b/ts/models/messages.ts
index 5891ed6f77..ba7816b346 100644
--- a/ts/models/messages.ts
+++ b/ts/models/messages.ts
@@ -173,6 +173,10 @@ import { GiftBadgeStates } from '../components/conversation/Message';
 import { downloadAttachment } from '../util/downloadAttachment';
 import type { StickerWithHydratedData } from '../types/Stickers';
 import { getStringForConversationMerge } from '../util/getStringForConversationMerge';
+import {
+  addToAttachmentDownloadQueue,
+  shouldUseAttachmentDownloadQueue,
+} from '../util/attachmentDownloadQueue';
 import { getTitleNoDefault, getNumber } from '../util/getTitle';
 import dataInterface from '../sql/Client';
 
@@ -346,6 +350,10 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
   }
 
   notifyRedux(): void {
+    if (!window.reduxActions) {
+      return;
+    }
+
     const { storyChanged } = window.reduxActions.stories;
 
     if (isStory(this.attributes)) {
@@ -2989,12 +2997,8 @@ export class MessageModel extends window.Backbone.Model<MessageAttributesType> {
           (conversation.getAccepted() || isOutgoing(message.attributes)) &&
           !shouldHoldOffDownload
         ) {
-          if (window.attachmentDownloadQueue) {
-            window.attachmentDownloadQueue.unshift(message);
-            log.info(
-              `${idLog}: Adding to attachmentDownloadQueue`,
-              message.get('sent_at')
-            );
+          if (shouldUseAttachmentDownloadQueue()) {
+            addToAttachmentDownloadQueue(idLog, message);
           } else {
             await message.queueAttachmentDownloads();
           }
diff --git a/ts/scripts/copy-and-concat.ts b/ts/scripts/copy.ts
similarity index 50%
rename from ts/scripts/copy-and-concat.ts
rename to ts/scripts/copy.ts
index d70f38f72a..56311bbf4a 100644
--- a/ts/scripts/copy-and-concat.ts
+++ b/ts/scripts/copy.ts
@@ -1,30 +1,10 @@
 // Copyright 2021 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-import { basename, join } from 'path';
-import { copyFileSync, readFileSync, writeFileSync } from 'fs';
-
-// Concat
-
-console.log('Concatenating...');
+import { join } from 'path';
+import { copyFileSync } from 'fs';
 
 const BASE_BOWER = join(__dirname, '../../components');
-const CONCAT_TARGET = join(__dirname, '../../js/components.js');
-const CONCAT_SOURCES = [
-  join(BASE_BOWER, 'webaudiorecorder/lib/WebAudioRecorder.js'),
-];
-
-let concat = '// concatenated components.js';
-CONCAT_SOURCES.forEach(source => {
-  const contents = readFileSync(source, 'utf8');
-  const name = basename(source);
-
-  console.log(`Concatenating ${source}`);
-  concat += `\n\n// ${name}\n${contents}`;
-});
-
-console.log(`Writing to ${CONCAT_TARGET}`);
-writeFileSync(CONCAT_TARGET, concat);
 
 // Copy
 
diff --git a/ts/services/LinkPreview.ts b/ts/services/LinkPreview.ts
index d008d5c559..49cb9678af 100644
--- a/ts/services/LinkPreview.ts
+++ b/ts/services/LinkPreview.ts
@@ -24,6 +24,7 @@ import { SECOND } from '../util/durations';
 import { autoScale } from '../util/handleImageAttachment';
 import { dropNull } from '../util/dropNull';
 import { fileToBytes } from '../util/fileToBytes';
+import { imageToBlurHash } from '../util/imageToBlurHash';
 import { maybeParseUrl } from '../util/url';
 import { sniffImageMimeType } from '../util/sniffImageMimeType';
 import { drop } from '../util/drop';
@@ -343,7 +344,7 @@ async function getPreview(
       const data = await fileToBytes(withBlob.file);
       objectUrl = URL.createObjectURL(withBlob.file);
 
-      const blurHash = await window.imageToBlurHash(withBlob.file);
+      const blurHash = await imageToBlurHash(withBlob.file);
 
       const dimensions = await VisualAttachment.getImageDimensions({
         objectUrl,
@@ -535,7 +536,7 @@ async function getGroupPreview(
         data,
         size: data.byteLength,
         contentType: IMAGE_JPEG,
-        blurHash: await window.imageToBlurHash(
+        blurHash: await imageToBlurHash(
           new Blob([data], {
             type: IMAGE_JPEG,
           })
diff --git a/ts/services/audioRecorder.ts b/ts/services/audioRecorder.ts
index d5df6cc4c6..8212fac5ab 100644
--- a/ts/services/audioRecorder.ts
+++ b/ts/services/audioRecorder.ts
@@ -3,13 +3,13 @@
 
 import { requestMicrophonePermissions } from '../util/requestMicrophonePermissions';
 import * as log from '../logging/log';
-import type { WebAudioRecorderClass } from '../window.d';
+import type { WebAudioRecorder } from '../WebAudioRecorder';
 import * as Errors from '../types/errors';
 
 export class RecorderClass {
   private context?: AudioContext;
   private input?: GainNode;
-  private recorder?: WebAudioRecorderClass;
+  private recorder?: WebAudioRecorder;
   private source?: MediaStreamAudioSourceNode;
   private stream?: MediaStream;
   private blob?: Blob;
@@ -31,7 +31,7 @@ export class RecorderClass {
 
       // Reach in and terminate the web worker used by WebAudioRecorder, otherwise
       // it gets leaked due to a reference cycle with its onmessage listener
-      this.recorder.worker.terminate();
+      this.recorder.worker?.terminate();
       this.recorder = undefined;
     }
 
@@ -58,15 +58,16 @@ export class RecorderClass {
     this.context = new AudioContext();
     this.input = this.context.createGain();
 
-    this.recorder = new window.WebAudioRecorder(this.input, {
-      encoding: 'mp3',
-      workerDir: 'js/', // must end with slash
-      options: {
+    this.recorder = new window.WebAudioRecorder(
+      this.input,
+      {
         timeLimit: 60 + 3600, // one minute more than our UI-imposed limit
       },
-    });
-    this.recorder.onComplete = this.onComplete.bind(this);
-    this.recorder.onError = this.onError.bind(this);
+      {
+        onComplete: this.onComplete.bind(this),
+        onError: this.onError.bind(this),
+      }
+    );
 
     try {
       const stream = await navigator.mediaDevices.getUserMedia({
@@ -78,7 +79,7 @@ export class RecorderClass {
         const err = new Error(
           'Recorder/getUserMedia/stream: Missing context or input!'
         );
-        this.onError(this.recorder, err);
+        this.onError(this.recorder, String(err));
         throw err;
       }
       this.source = this.context.createMediaStreamSource(stream);
@@ -120,12 +121,12 @@ export class RecorderClass {
     return promise;
   }
 
-  onComplete(_recorder: WebAudioRecorderClass, blob: Blob): void {
+  onComplete(_recorder: WebAudioRecorder, blob: Blob): void {
     this.blob = blob;
     this.resolve?.(blob);
   }
 
-  onError(_recorder: WebAudioRecorderClass, error: Error): void {
+  onError(_recorder: WebAudioRecorder, error: string): void {
     if (!this.recorder) {
       log.warn('Recorder/onError: Called with no recorder');
       return;
diff --git a/ts/services/calling.ts b/ts/services/calling.ts
index 7bb06b5d45..a97e7aba51 100644
--- a/ts/services/calling.ts
+++ b/ts/services/calling.ts
@@ -1620,12 +1620,12 @@ export class CallingClass {
   }
 
   private async requestCameraPermissions(): Promise<boolean> {
-    const cameraPermission = await window.getMediaCameraPermissions();
+    const cameraPermission = await window.IPC.getMediaCameraPermissions();
     if (!cameraPermission) {
-      await window.showPermissionsPopup(true, true);
+      await window.IPC.showPermissionsPopup(true, true);
 
       // Check the setting again (from the source of truth).
-      return window.getMediaCameraPermissions();
+      return window.IPC.getMediaCameraPermissions();
     }
 
     return true;
diff --git a/ts/services/notifications.ts b/ts/services/notifications.ts
index 2e33c5453d..9650e85ff4 100644
--- a/ts/services/notifications.ts
+++ b/ts/services/notifications.ts
@@ -260,7 +260,7 @@ class NotificationService extends EventEmitter {
     );
     if (shouldDrawAttention) {
       log.info('NotificationService: drawing attention');
-      window.drawAttention();
+      window.IPC.drawAttention();
     }
 
     let notificationTitle: string;
diff --git a/ts/services/storage.ts b/ts/services/storage.ts
index f23d9724d8..b8833d7534 100644
--- a/ts/services/storage.ts
+++ b/ts/services/storage.ts
@@ -1733,8 +1733,8 @@ async function sync(
     // We now know that we've successfully completed a storage service fetch
     await window.storage.put('storageFetchComplete', true);
 
-    if (window.CI) {
-      window.CI.handleEvent('storageServiceComplete', {
+    if (window.Signal.CI) {
+      window.Signal.CI.handleEvent('storageServiceComplete', {
         manifestVersion: version,
       });
     }
diff --git a/ts/set_os_class.ts b/ts/set_os_class.ts
deleted file mode 100644
index cf9f0c3b5d..0000000000
--- a/ts/set_os_class.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright 2021 Signal Messenger, LLC
-// SPDX-License-Identifier: AGPL-3.0-only
-
-{
-  let className: string;
-  if (window.SignalContext.OS.isWindows()) {
-    className = 'os-windows';
-  } else if (window.SignalContext.OS.isMacOS()) {
-    className = 'os-macos';
-  } else if (window.SignalContext.OS.isLinux()) {
-    className = 'os-linux';
-  } else {
-    throw new Error('Unexpected operating system; not applying ');
-  }
-
-  document.body.classList.add(className);
-
-  if (window.SignalContext.OS.hasCustomTitleBar()) {
-    document.body.classList.add('os-has-custom-titlebar');
-  }
-}
diff --git a/ts/shims/Whisper.ts b/ts/shims/Whisper.ts
index f995b89108..b4b20a5bdf 100644
--- a/ts/shims/Whisper.ts
+++ b/ts/shims/Whisper.ts
@@ -2,5 +2,5 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 export function showSettings(): void {
-  window.showSettings();
+  window.IPC.showSettings();
 }
diff --git a/ts/shims/deleteAllData.ts b/ts/shims/deleteAllData.ts
index 45ee2a0b2e..c000717908 100644
--- a/ts/shims/deleteAllData.ts
+++ b/ts/shims/deleteAllData.ts
@@ -32,5 +32,5 @@ export async function deleteAllData(): Promise<void> {
       Errors.toLogFormat(error)
     );
   }
-  window.restart();
+  window.IPC.restart();
 }
diff --git a/ts/signal.ts b/ts/signal.ts
index dde7fad19d..7cfb19a1be 100644
--- a/ts/signal.ts
+++ b/ts/signal.ts
@@ -13,36 +13,13 @@ import * as RemoteConfig from './RemoteConfig';
 import * as Util from './util';
 
 // Components
-import { AttachmentList } from './components/conversation/AttachmentList';
-import { ChatColorPicker } from './components/ChatColorPicker';
 import { ConfirmationDialog } from './components/ConfirmationDialog';
-import { ContactModal } from './components/conversation/ContactModal';
-import { Emojify } from './components/conversation/Emojify';
-import { MessageDetail } from './components/conversation/MessageDetail';
-import { Quote } from './components/conversation/Quote';
-import { StagedLinkPreview } from './components/conversation/StagedLinkPreview';
-import { DisappearingTimeDialog } from './components/DisappearingTimeDialog';
 
 // State
 import { createApp } from './state/roots/createApp';
 import { createSafetyNumberViewer } from './state/roots/createSafetyNumberViewer';
 
 import { createStore } from './state/createStore';
-import * as appDuck from './state/ducks/app';
-import * as callingDuck from './state/ducks/calling';
-import * as conversationsDuck from './state/ducks/conversations';
-import * as emojisDuck from './state/ducks/emojis';
-import * as expirationDuck from './state/ducks/expiration';
-import * as itemsDuck from './state/ducks/items';
-import * as linkPreviewsDuck from './state/ducks/linkPreviews';
-import * as networkDuck from './state/ducks/network';
-import * as searchDuck from './state/ducks/search';
-import * as stickersDuck from './state/ducks/stickers';
-import * as updatesDuck from './state/ducks/updates';
-import * as userDuck from './state/ducks/user';
-
-import * as conversationsSelectors from './state/selectors/conversations';
-import * as searchSelectors from './state/selectors/search';
 
 // Types
 import * as TypesAttachment from './types/Attachment';
@@ -378,15 +355,7 @@ export const setup = (options: {
   });
 
   const Components = {
-    AttachmentList,
-    ChatColorPicker,
     ConfirmationDialog,
-    ContactModal,
-    Emojify,
-    MessageDetail,
-    Quote,
-    StagedLinkPreview,
-    DisappearingTimeDialog,
   };
 
   const Roots = {
@@ -394,26 +363,6 @@ export const setup = (options: {
     createSafetyNumberViewer,
   };
 
-  const Ducks = {
-    app: appDuck,
-    calling: callingDuck,
-    conversations: conversationsDuck,
-    emojis: emojisDuck,
-    expiration: expirationDuck,
-    items: itemsDuck,
-    linkPreviews: linkPreviewsDuck,
-    network: networkDuck,
-    updates: updatesDuck,
-    user: userDuck,
-    search: searchDuck,
-    stickers: stickersDuck,
-  };
-
-  const Selectors = {
-    conversations: conversationsSelectors,
-    search: searchSelectors,
-  };
-
   const Services = {
     calling,
     initializeGroupCredentialFetcher,
@@ -427,8 +376,6 @@ export const setup = (options: {
   const State = {
     createStore,
     Roots,
-    Ducks,
-    Selectors,
   };
 
   const Types = {
diff --git a/ts/state/ducks/app.ts b/ts/state/ducks/app.ts
index 83828f2c3e..b84ea5a16c 100644
--- a/ts/state/ducks/app.ts
+++ b/ts/state/ducks/app.ts
@@ -85,7 +85,7 @@ function openInstaller(): ThunkAction<
   OpenInstallerActionType
 > {
   return dispatch => {
-    window.addSetupMenuItems();
+    window.IPC.addSetupMenuItems();
 
     dispatch({
       type: OPEN_INSTALLER,
@@ -104,7 +104,7 @@ function openStandalone(): ThunkAction<
       return;
     }
 
-    window.addSetupMenuItems();
+    window.IPC.addSetupMenuItems();
     dispatch({
       type: OPEN_STANDALONE,
     });
diff --git a/ts/state/ducks/crashReports.ts b/ts/state/ducks/crashReports.ts
index 0f6204a29a..574865e07d 100644
--- a/ts/state/ducks/crashReports.ts
+++ b/ts/state/ducks/crashReports.ts
@@ -44,11 +44,11 @@ function setCrashReportCount(count: number): SetCrashReportCountActionType {
 }
 
 function uploadCrashReports(): PromiseAction<typeof UPLOAD> {
-  return { type: UPLOAD, payload: window.crashReports.upload() };
+  return { type: UPLOAD, payload: window.IPC.crashReports.upload() };
 }
 
 function eraseCrashReports(): PromiseAction<typeof ERASE> {
-  return { type: ERASE, payload: window.crashReports.erase() };
+  return { type: ERASE, payload: window.IPC.crashReports.erase() };
 }
 
 // Reducer
diff --git a/ts/state/ducks/user.ts b/ts/state/ducks/user.ts
index 9e963f3ee6..58944282bc 100644
--- a/ts/state/ducks/user.ts
+++ b/ts/state/ducks/user.ts
@@ -3,32 +3,34 @@
 
 import { trigger } from '../../shims/events';
 
-import type { NoopActionType } from './noop';
-import type { LocalizerType } from '../../types/Util';
 import type { LocaleMessagesType } from '../../types/I18N';
-import { ThemeType } from '../../types/Util';
-import type { UUIDStringType } from '../../types/UUID';
+import type { LocalizerType } from '../../types/Util';
 import type { MenuOptionsType } from '../../types/menu';
+import type { NoopActionType } from './noop';
+import type { UUIDStringType } from '../../types/UUID';
+import * as OS from '../../OS';
+import { ThemeType } from '../../types/Util';
 
 // State
 
 export type UserStateType = {
   attachmentsPath: string;
-  stickersPath: string;
-  tempPath: string;
+  i18n: LocalizerType;
+  interactionMode: 'mouse' | 'keyboard';
+  isMainWindowFullScreen: boolean;
+  isMainWindowMaximized: boolean;
+  localeMessages: LocaleMessagesType;
+  menuOptions: MenuOptionsType;
+  osName: 'linux' | 'macos' | 'windows' | undefined;
+  ourACI: UUIDStringType | undefined;
   ourConversationId: string | undefined;
   ourDeviceId: number | undefined;
-  ourACI: UUIDStringType | undefined;
-  ourPNI: UUIDStringType | undefined;
   ourNumber: string | undefined;
+  ourPNI: UUIDStringType | undefined;
   platform: string;
   regionCode: string | undefined;
-  i18n: LocalizerType;
-  localeMessages: LocaleMessagesType;
-  interactionMode: 'mouse' | 'keyboard';
-  isMainWindowMaximized: boolean;
-  isMainWindowFullScreen: boolean;
-  menuOptions: MenuOptionsType;
+  stickersPath: string;
+  tempPath: string;
   theme: ThemeType;
   version: string;
 };
@@ -96,20 +98,27 @@ const intlNotSetup = () => {
 // Reducer
 
 export function getEmptyState(): UserStateType {
+  let osName: 'windows' | 'macos' | 'linux' | undefined;
+
+  if (OS.isWindows()) {
+    osName = 'windows';
+  } else if (OS.isMacOS()) {
+    osName = 'macos';
+  } else if (OS.isLinux()) {
+    osName = 'linux';
+  }
+
   return {
     attachmentsPath: 'missing',
-    stickersPath: 'missing',
-    tempPath: 'missing',
-    ourConversationId: 'missing',
-    ourDeviceId: 0,
-    ourACI: undefined,
-    ourPNI: undefined,
-    ourNumber: 'missing',
-    regionCode: 'missing',
-    platform: 'missing',
+    i18n: Object.assign(intlNotSetup, {
+      getLocale: intlNotSetup,
+      getIntl: intlNotSetup,
+      isLegacyFormat: intlNotSetup,
+    }),
     interactionMode: 'mouse',
     isMainWindowMaximized: false,
     isMainWindowFullScreen: false,
+    localeMessages: {},
     menuOptions: {
       development: false,
       devTools: false,
@@ -117,13 +126,17 @@ export function getEmptyState(): UserStateType {
       isProduction: true,
       platform: 'unknown',
     },
+    osName,
+    ourACI: undefined,
+    ourConversationId: 'missing',
+    ourDeviceId: 0,
+    ourNumber: 'missing',
+    ourPNI: undefined,
+    platform: 'missing',
+    regionCode: 'missing',
+    stickersPath: 'missing',
+    tempPath: 'missing',
     theme: ThemeType.light,
-    i18n: Object.assign(intlNotSetup, {
-      getLocale: intlNotSetup,
-      getIntl: intlNotSetup,
-      isLegacyFormat: intlNotSetup,
-    }),
-    localeMessages: {},
     version: '0.0.0',
   };
 }
diff --git a/ts/state/getInitialState.ts b/ts/state/getInitialState.ts
index 61cf1e4a32..4d0ce96139 100644
--- a/ts/state/getInitialState.ts
+++ b/ts/state/getInitialState.ts
@@ -26,15 +26,15 @@ import { getEmptyState as user } from './ducks/user';
 import { getEmptyState as username } from './ducks/username';
 
 import type { StateType } from './reducer';
-
 import type { BadgesStateType } from './ducks/badges';
+import type { MainWindowStatsType } from '../windows/context';
+import type { MenuOptionsType } from '../types/menu';
 import type { StoryDataType } from './ducks/stories';
 import type { StoryDistributionListDataType } from './ducks/storyDistributionLists';
-import { getInitialState as stickers } from '../types/Stickers';
-import type { MenuOptionsType } from '../types/menu';
+import * as OS from '../OS';
 import { UUIDKind } from '../types/UUID';
 import { getEmojiReducerState as emojis } from '../util/loadRecentEmojis';
-import type { MainWindowStatsType } from '../windows/context';
+import { getInitialState as stickers } from '../types/Stickers';
 import { getThemeType } from '../util/getThemeType';
 
 export function getInitialState({
@@ -69,6 +69,16 @@ export function getInitialState({
 
   const theme = getThemeType();
 
+  let osName: 'windows' | 'macos' | 'linux' | undefined;
+
+  if (OS.isWindows()) {
+    osName = 'windows';
+  } else if (OS.isMacOS()) {
+    osName = 'macos';
+  } else if (OS.isLinux()) {
+    osName = 'linux';
+  }
+
   return {
     accounts: accounts(),
     app: app(),
@@ -125,24 +135,25 @@ export function getInitialState({
     updates: updates(),
     user: {
       ...user(),
-      attachmentsPath: window.baseAttachmentsPath,
-      stickersPath: window.baseStickersPath,
-      tempPath: window.baseTempPath,
-      regionCode: window.storage.get('regionCode'),
+      attachmentsPath: window.BasePaths.attachments,
+      i18n: window.i18n,
+      interactionMode: window.getInteractionMode(),
+      isMainWindowFullScreen: mainWindowStats.isFullScreen,
+      isMainWindowMaximized: mainWindowStats.isMaximized,
+      localeMessages: window.SignalContext.localeMessages,
+      menuOptions,
+      osName,
+      ourACI,
       ourConversationId,
       ourDeviceId,
       ourNumber,
-      ourACI,
       ourPNI,
       platform: window.platform,
-      i18n: window.i18n,
-      localeMessages: window.SignalContext.localeMessages,
-      interactionMode: window.getInteractionMode(),
+      regionCode: window.storage.get('regionCode'),
+      stickersPath: window.BasePaths.stickers,
+      tempPath: window.BasePaths.temp,
       theme,
       version: window.getVersion(),
-      isMainWindowMaximized: mainWindowStats.isMaximized,
-      isMainWindowFullScreen: mainWindowStats.isFullScreen,
-      menuOptions,
     },
     username: username(),
   };
diff --git a/ts/state/smart/App.tsx b/ts/state/smart/App.tsx
index 891ef5542d..10a099ce30 100644
--- a/ts/state/smart/App.tsx
+++ b/ts/state/smart/App.tsx
@@ -38,6 +38,18 @@ function renderInbox(): JSX.Element {
 const mapStateToProps = (state: StateType) => {
   const i18n = getIntl(state);
 
+  const { osName } = state.user;
+
+  let osClassName = '';
+
+  if (osName === 'windows') {
+    osClassName = 'os-windows';
+  } else if (osName === 'macos') {
+    osClassName = 'os-macos';
+  } else if (osName === 'linux') {
+    osClassName = 'os-linux';
+  }
+
   return {
     ...state.app,
     i18n,
@@ -46,6 +58,7 @@ const mapStateToProps = (state: StateType) => {
     isFullScreen: getIsMainWindowFullScreen(state),
     menuOptions: getMenuOptions(state),
     hasCustomTitleBar: window.SignalContext.OS.hasCustomTitleBar(),
+    osClassName,
     hideMenuBar: getHideMenuBar(state),
     renderCallManager: () => (
       <ModalContainer className="module-calling__modal-container">
@@ -92,7 +105,7 @@ const mapStateToProps = (state: StateType) => {
       void window.SignalContext.executeMenuAction(action);
     },
     titleBarDoubleClick: (): void => {
-      window.titleBarDoubleClick();
+      window.IPC.titleBarDoubleClick();
     },
     toast: state.toast.toast,
   };
diff --git a/ts/state/smart/CallManager.tsx b/ts/state/smart/CallManager.tsx
index 27ae485cf9..0f11e241b9 100644
--- a/ts/state/smart/CallManager.tsx
+++ b/ts/state/smart/CallManager.tsx
@@ -87,7 +87,7 @@ async function notifyForCall(
       isVideoCall ? 'incomingVideoCall' : 'incomingAudioCall'
     ),
     onNotificationClick: () => {
-      window.showWindow();
+      window.IPC.showWindow();
     },
     silent: false,
   });
diff --git a/ts/state/smart/InstallScreen.tsx b/ts/state/smart/InstallScreen.tsx
index f096db4554..cedc585d32 100644
--- a/ts/state/smart/InstallScreen.tsx
+++ b/ts/state/smart/InstallScreen.tsx
@@ -164,8 +164,10 @@ export function SmartInstallScreen(): ReactElement {
       }
       onQrCodeScanned();
 
-      if (window.CI) {
-        chooseDeviceNamePromiseWrapperRef.current.resolve(window.CI.deviceName);
+      if (window.Signal.CI) {
+        chooseDeviceNamePromiseWrapperRef.current.resolve(
+          window.Signal.CI.deviceName
+        );
       }
 
       const result = await chooseDeviceNamePromiseWrapperRef.current.promise;
@@ -203,7 +205,7 @@ export function SmartInstallScreen(): ReactElement {
           confirmNumber
         );
 
-        window.removeSetupMenuItems();
+        window.IPC.removeSetupMenuItems();
       } catch (error) {
         log.error(
           'account.registerSecondDevice: got an error',
@@ -233,7 +235,7 @@ export function SmartInstallScreen(): ReactElement {
         screenSpecificProps: {
           i18n,
           error: state.error,
-          quit: () => window.shutdown(),
+          quit: () => window.IPC.shutdown(),
           tryAgain: () => setState(INITIAL_STATE),
         },
       };
diff --git a/ts/test-mock/benchmarks/convo_open_bench.ts b/ts/test-mock/benchmarks/convo_open_bench.ts
index e21c6f4793..5e4865c4b0 100644
--- a/ts/test-mock/benchmarks/convo_open_bench.ts
+++ b/ts/test-mock/benchmarks/convo_open_bench.ts
@@ -69,8 +69,7 @@ void (async () => {
       const openConvo = async (contact: PrimaryDevice): Promise<void> => {
         debug('opening conversation', contact.profileName);
         const item = leftPane.locator(
-          '_react=BaseConversationListItem' +
-            `[title = ${JSON.stringify(contact.profileName)}]`
+          `[data-testid="${contact.toContact().uuid}"]`
         );
 
         await item.click();
diff --git a/ts/test-mock/benchmarks/group_send_bench.ts b/ts/test-mock/benchmarks/group_send_bench.ts
index 7d4bf957d6..42ade93e3c 100644
--- a/ts/test-mock/benchmarks/group_send_bench.ts
+++ b/ts/test-mock/benchmarks/group_send_bench.ts
@@ -122,11 +122,9 @@ void (async () => {
     {
       const leftPane = window.locator('.left-pane-wrapper');
 
-      const item = leftPane.locator(
-        '_react=BaseConversationListItem' +
-          `[title = ${JSON.stringify(group.title)}] ` +
-          `>> text=${LAST_MESSAGE}`
-      );
+      const item = leftPane
+        .locator('.module-conversation-list__item--contact-or-conversation')
+        .first();
       await item.click();
     }
 
@@ -141,7 +139,7 @@ void (async () => {
         '.composition-area-wrapper, .conversation .ConversationView'
       );
 
-      const input = composeArea.locator('_react=CompositionInput');
+      const input = composeArea.locator('[data-testid=CompositionInput]');
 
       debug('entering message text');
       await input.type(`my message ${runId}`);
@@ -166,9 +164,7 @@ void (async () => {
       await server.send(desktop, delivery);
 
       debug('waiting for message state change');
-      const message = timeline.locator(
-        `_react=Message[timestamp = ${timestamp}][status = "delivered"]`
-      );
+      const message = timeline.locator(`[data-testid="${timestamp}"]`);
       await message.waitFor();
 
       if (runId >= DISCARD_COUNT) {
diff --git a/ts/test-mock/benchmarks/send_bench.ts b/ts/test-mock/benchmarks/send_bench.ts
index 9bca7e9426..ec98add489 100644
--- a/ts/test-mock/benchmarks/send_bench.ts
+++ b/ts/test-mock/benchmarks/send_bench.ts
@@ -75,9 +75,7 @@ void (async () => {
     {
       const leftPane = window.locator('.left-pane-wrapper');
       const item = leftPane.locator(
-        '_react=BaseConversationListItem' +
-          `[title = ${JSON.stringify(first.profileName)}]` +
-          `>> ${JSON.stringify(LAST_MESSAGE)}`
+        `[data-testid="${first.toContact().uuid}"]`
       );
       await item.click();
     }
@@ -92,7 +90,7 @@ void (async () => {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const input = composeArea.locator('_react=CompositionInput');
+      const input = composeArea.locator('[data-testid=CompositionInput]');
 
       debug('entering message text');
       await input.type(`my message ${runId}`);
@@ -116,9 +114,7 @@ void (async () => {
       await server.send(desktop, delivery);
 
       debug('waiting for message state change');
-      const message = timeline.locator(
-        `_react=Message[timestamp = ${timestamp}][status = "delivered"]`
-      );
+      const message = timeline.locator(`[data-testid="${timestamp}"]`);
       await message.waitFor();
 
       if (runId >= DISCARD_COUNT) {
diff --git a/ts/test-mock/benchmarks/storage_sync_bench.ts b/ts/test-mock/benchmarks/storage_sync_bench.ts
index 4a103fbaed..6006a30e28 100644
--- a/ts/test-mock/benchmarks/storage_sync_bench.ts
+++ b/ts/test-mock/benchmarks/storage_sync_bench.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 /* eslint-disable no-await-in-loop, no-console */
 
+import type { PrimaryDevice } from '@signalapp/mock-server';
 import { StorageState } from '@signalapp/mock-server';
 
 import type { App } from './fixtures';
@@ -23,6 +24,7 @@ void (async () => {
   const { phone, server } = bootstrap;
 
   let state = StorageState.getEmpty();
+  let lastContact: PrimaryDevice | undefined;
   for (const [i, profileName] of contactNames.entries()) {
     const contact = await server.createPrimaryDevice({
       profileName,
@@ -39,6 +41,10 @@ void (async () => {
     if (i >= contactNames.length - 4) {
       state = state.pin(contact);
     }
+
+    if (i === contactNames.length - 1) {
+      lastContact = contact;
+    }
   }
 
   await phone.setStorageState(state);
@@ -52,8 +58,7 @@ void (async () => {
     const leftPane = window.locator('.left-pane-wrapper');
 
     const item = leftPane.locator(
-      '_react=BaseConversationListItem' +
-        `[title = ${JSON.stringify(contactNames[contactNames.length - 1])}]`
+      `[data-testid="${lastContact?.toContact().uuid}"]`
     );
     await item.waitFor();
 
diff --git a/ts/test-mock/playwright.ts b/ts/test-mock/playwright.ts
index 7f73211b31..c6736e7a3c 100644
--- a/ts/test-mock/playwright.ts
+++ b/ts/test-mock/playwright.ts
@@ -89,7 +89,7 @@ export class App {
     const window = await this.getWindow();
 
     await window.evaluate(
-      `window.CI.solveChallenge(${JSON.stringify(response)})`
+      `window.Signal.CI.solveChallenge(${JSON.stringify(response)})`
     );
   }
 
@@ -105,7 +105,7 @@ export class App {
     const window = await this.getWindow();
 
     const result = await window.evaluate(
-      `window.CI.waitForEvent(${JSON.stringify(event)})`
+      `window.Signal.CI.waitForEvent(${JSON.stringify(event)})`
     );
 
     return result as T;
diff --git a/ts/test-mock/pnp/accept_gv2_invite_test.ts b/ts/test-mock/pnp/accept_gv2_invite_test.ts
index 307bb83771..cfec47dbbd 100644
--- a/ts/test-mock/pnp/accept_gv2_invite_test.ts
+++ b/ts/test-mock/pnp/accept_gv2_invite_test.ts
@@ -52,12 +52,7 @@ describe('pnp/accept gv2 invite', function needsName() {
     const leftPane = window.locator('.left-pane-wrapper');
 
     debug('Opening group');
-    await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(group.title)}]`
-      )
-      .click();
+    await leftPane.locator(`[data-testid="${group.id}"]`).click();
   });
 
   afterEach(async function after() {
@@ -296,12 +291,7 @@ describe('pnp/accept gv2 invite', function needsName() {
     const leftPane = window.locator('.left-pane-wrapper');
 
     debug('Opening new group');
-    await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(group.title)}]`
-      )
-      .click();
+    await leftPane.locator(`[data-testid="${group.id}"]`).click();
 
     debug('Accepting remote invite');
     await second.acceptPniInvite(group, desktop, {
diff --git a/ts/test-mock/pnp/change_number_test.ts b/ts/test-mock/pnp/change_number_test.ts
index c8b2b255de..e128f6078d 100644
--- a/ts/test-mock/pnp/change_number_test.ts
+++ b/ts/test-mock/pnp/change_number_test.ts
@@ -64,13 +64,7 @@ describe('pnp/change number', function needsName() {
     ]);
 
     debug('opening conversation with the first contact');
-    await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(first.profileName)}] ` +
-          ' >> "After"'
-      )
-      .click();
+    await leftPane.locator(`[data-testid="${first.toContact().uuid}"]`).click();
 
     debug('done');
   });
diff --git a/ts/test-mock/pnp/merge_test.ts b/ts/test-mock/pnp/merge_test.ts
index 517272949f..cace590754 100644
--- a/ts/test-mock/pnp/merge_test.ts
+++ b/ts/test-mock/pnp/merge_test.ts
@@ -109,7 +109,7 @@ describe('pnp/merge', function needsName() {
 
       debug('opening conversation with the aci contact');
       await leftPane
-        .locator('_react=ConversationListItem[title = "ACI Contact"]')
+        .locator(`[data-testid="${pniContact.toContact().uuid}"]`)
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -119,7 +119,9 @@ describe('pnp/merge', function needsName() {
         const composeArea = window.locator(
           '.composition-area-wrapper, .conversation .ConversationView'
         );
-        const compositionInput = composeArea.locator('_react=CompositionInput');
+        const compositionInput = composeArea.locator(
+          '[data-testid=CompositionInput]'
+        );
 
         await compositionInput.type('Hello ACI');
         await compositionInput.press('Enter');
@@ -127,7 +129,8 @@ describe('pnp/merge', function needsName() {
 
       debug('opening conversation with the pni contact');
       await leftPane
-        .locator('_react=ConversationListItem[title = "PNI Contact"]')
+        .locator('.module-conversation-list__item--contact-or-conversation')
+        .first()
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -152,7 +155,9 @@ describe('pnp/merge', function needsName() {
         const composeArea = window.locator(
           '.composition-area-wrapper, .conversation .ConversationView'
         );
-        const compositionInput = composeArea.locator('_react=CompositionInput');
+        const compositionInput = composeArea.locator(
+          '[data-testid=CompositionInput]'
+        );
 
         await compositionInput.type('Hello PNI');
         await compositionInput.press('Enter');
@@ -161,7 +166,7 @@ describe('pnp/merge', function needsName() {
       if (finalContact === UUIDKind.ACI) {
         debug('switching back to ACI conversation');
         await leftPane
-          .locator('_react=ConversationListItem[title = "ACI Contact"]')
+          .locator(`[data-testid="${pniContact.toContact().uuid}"]`)
           .click();
 
         await window.locator('.module-conversation-hero').waitFor();
diff --git a/ts/test-mock/pnp/pni_change_test.ts b/ts/test-mock/pnp/pni_change_test.ts
index ce9451ec09..0851324510 100644
--- a/ts/test-mock/pnp/pni_change_test.ts
+++ b/ts/test-mock/pnp/pni_change_test.ts
@@ -80,7 +80,9 @@ describe('pnp/PNI Change', function needsName() {
       const leftPane = window.locator('.left-pane-wrapper');
 
       await leftPane
-        .locator('_react=ConversationListItem[title = "ContactA"]')
+        .locator(
+          `[data-testid="${contactA.device.getUUIDByKind(UUIDKind.PNI)}"]`
+        )
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -102,7 +104,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('message to contactA');
       await compositionInput.press('Enter');
@@ -181,7 +185,9 @@ describe('pnp/PNI Change', function needsName() {
       const leftPane = window.locator('.left-pane-wrapper');
 
       await leftPane
-        .locator('_react=ConversationListItem[title = "ContactA"]')
+        .locator(
+          `[data-testid="${contactA.device.getUUIDByKind(UUIDKind.PNI)}"]`
+        )
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -203,7 +209,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('message to contactA');
       await compositionInput.press('Enter');
@@ -284,7 +292,9 @@ describe('pnp/PNI Change', function needsName() {
       const leftPane = window.locator('.left-pane-wrapper');
 
       await leftPane
-        .locator('_react=ConversationListItem[title = "ContactA"]')
+        .locator(
+          `[data-testid="${contactA.device.getUUIDByKind(UUIDKind.PNI)}"]`
+        )
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -306,7 +316,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('message to contactA');
       await compositionInput.press('Enter');
@@ -366,7 +378,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('message to contactB');
       await compositionInput.press('Enter');
@@ -420,7 +434,9 @@ describe('pnp/PNI Change', function needsName() {
       const leftPane = window.locator('.left-pane-wrapper');
 
       await leftPane
-        .locator('_react=ConversationListItem[title = "ContactA"]')
+        .locator(
+          `[data-testid="${contactA.device.getUUIDByKind(UUIDKind.PNI)}"]`
+        )
         .click();
 
       await window.locator('.module-conversation-hero').waitFor();
@@ -442,7 +458,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('message to contactA');
       await compositionInput.press('Enter');
@@ -533,7 +551,9 @@ describe('pnp/PNI Change', function needsName() {
       const composeArea = window.locator(
         '.composition-area-wrapper, .conversation .ConversationView'
       );
-      const compositionInput = composeArea.locator('_react=CompositionInput');
+      const compositionInput = composeArea.locator(
+        '[data-testid=CompositionInput]'
+      );
 
       await compositionInput.type('second message to contactA');
       await compositionInput.press('Enter');
diff --git a/ts/test-mock/pnp/pni_signature_test.ts b/ts/test-mock/pnp/pni_signature_test.ts
index 6748599853..1113d8cbe6 100644
--- a/ts/test-mock/pnp/pni_signature_test.ts
+++ b/ts/test-mock/pnp/pni_signature_test.ts
@@ -153,10 +153,7 @@ describe('pnp/PNI Signature', function needsName() {
 
     debug('opening conversation with the stranger');
     await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(stranger.profileName)}]`
-      )
+      .locator(`[data-testid="${stranger.toContact().uuid}"]`)
       .click();
 
     debug('Accept conversation from a stranger');
@@ -173,7 +170,9 @@ describe('pnp/PNI Signature', function needsName() {
     }
 
     debug('Enter first message text');
-    const compositionInput = composeArea.locator('_react=CompositionInput');
+    const compositionInput = composeArea.locator(
+      '[data-testid=CompositionInput]'
+    );
 
     await compositionInput.type('first');
     await compositionInput.press('Enter');
@@ -273,11 +272,14 @@ describe('pnp/PNI Signature', function needsName() {
 
     debug('opening conversation with the pni contact');
     await leftPane
-      .locator('_react=ConversationListItem[title = "PNI Contact"]')
+      .locator('.module-conversation-list__item--contact-or-conversation')
+      .first()
       .click();
 
     debug('Enter a PNI message text');
-    const compositionInput = composeArea.locator('_react=CompositionInput');
+    const compositionInput = composeArea.locator(
+      '[data-testid=CompositionInput]'
+    );
 
     await compositionInput.type('Hello PNI');
     await compositionInput.press('Enter');
@@ -313,13 +315,11 @@ describe('pnp/PNI Signature', function needsName() {
 
     debug('Wait for merge to happen');
     await leftPane
-      .locator('_react=ConversationListItem[title = "ACI Contact"]')
+      .locator(`[data-testid="${pniContact.toContact().uuid}"]`)
       .waitFor();
 
     debug('Wait for composition input to clear');
-    await composeArea
-      .locator('_react=CompositionInput[draftText = ""]')
-      .waitFor();
+    await composeArea.locator('[data-testid=CompositionInput]').waitFor();
 
     debug('Enter an ACI message text');
     await compositionInput.type('Hello ACI');
diff --git a/ts/test-mock/pnp/send_gv2_invite_test.ts b/ts/test-mock/pnp/send_gv2_invite_test.ts
index 90a695e68b..496b250c46 100644
--- a/ts/test-mock/pnp/send_gv2_invite_test.ts
+++ b/ts/test-mock/pnp/send_gv2_invite_test.ts
@@ -105,9 +105,7 @@ describe('pnp/send gv2 invite', function needsName() {
 
     await leftPane.locator('.module-main-header__compose-icon').click();
 
-    await leftPane
-      .locator('_react=BaseConversationListItem[title = "New group"]')
-      .click();
+    await leftPane.locator('[data-testid=CreateNewGroupButton]').click();
 
     debug('inviting ACI member');
 
@@ -116,7 +114,7 @@ describe('pnp/send gv2 invite', function needsName() {
       .fill('ACI');
 
     await leftPane
-      .locator('_react=BaseConversationListItem[title = "ACI Contact"]')
+      .locator(`[data-testid="${aciContact.toContact().uuid}"]`)
       .click();
 
     debug('inviting PNI member');
@@ -126,7 +124,9 @@ describe('pnp/send gv2 invite', function needsName() {
       .fill('PNI');
 
     await leftPane
-      .locator('_react=BaseConversationListItem[title = "PNI Contact"]')
+      .locator(
+        `[data-testid="${pniContact.device.getUUIDByKind(UUIDKind.PNI)}"]`
+      )
       .click();
 
     await leftPane
@@ -180,7 +180,7 @@ describe('pnp/send gv2 invite', function needsName() {
     debug('editing group title');
     {
       const detailsHeader = conversationStack.locator(
-        '_react=ConversationDetailsHeader'
+        '[data-testid=ConversationDetailsHeader]'
       );
       await detailsHeader.locator('button >> "My group"').click();
 
diff --git a/ts/test-mock/storage/archive_test.ts b/ts/test-mock/storage/archive_test.ts
index 14b7b01cef..4fa4a6d7dc 100644
--- a/ts/test-mock/storage/archive_test.ts
+++ b/ts/test-mock/storage/archive_test.ts
@@ -53,10 +53,7 @@ describe('storage service', function needsName() {
       });
 
       await leftPane
-        .locator(
-          '_react=ConversationListItem' +
-            `[title = ${JSON.stringify(firstContact.profileName)}]`
-        )
+        .locator(`[data-testid="${firstContact.toContact().uuid}"]`)
         .waitFor({ state: 'hidden' });
 
       await leftPane
@@ -76,11 +73,7 @@ describe('storage service', function needsName() {
       });
 
       await leftPane
-        .locator(
-          '_react=ConversationListItem' +
-            '[isPinned = true]' +
-            `[title = ${JSON.stringify(firstContact.profileName)}]`
-        )
+        .locator(`[data-testid="${firstContact.toContact().uuid}"]`)
         .waitFor();
 
       await leftPane
@@ -93,10 +86,7 @@ describe('storage service', function needsName() {
       const state = await phone.expectStorageState('consistency check');
 
       await leftPane
-        .locator(
-          '_react=ConversationListItem' +
-            `[title = ${JSON.stringify(firstContact.profileName)}]`
-        )
+        .locator(`[data-testid="${firstContact.toContact().uuid}"]`)
         .click();
 
       const moreButton = conversationStack.locator(
diff --git a/ts/test-mock/storage/max_read_keys_test.ts b/ts/test-mock/storage/max_read_keys_test.ts
index 7308a357ca..847a90314e 100644
--- a/ts/test-mock/storage/max_read_keys_test.ts
+++ b/ts/test-mock/storage/max_read_keys_test.ts
@@ -48,11 +48,7 @@ describe('storage service', function needsName() {
 
     debug('wait for first contact to be pinned in the left pane');
     await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          '[isPinned = true] ' +
-          `[title = ${JSON.stringify(firstContact.profileName)}]`
-      )
+      .locator(`[data-testid="${firstContact.toContact().uuid}"]`)
       .waitFor();
 
     {
@@ -83,11 +79,7 @@ describe('storage service', function needsName() {
 
     debug('wait for last contact to be pinned in the left pane');
     await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          '[isPinned = true] ' +
-          `[title = ${JSON.stringify(lastContact.profileName)}]`
-      )
+      .locator(`[data-testid="${lastContact.toContact().uuid}"]`)
       .waitFor({ timeout: durations.MINUTE });
 
     debug('Verifying the final manifest version');
diff --git a/ts/test-mock/storage/message_request_test.ts b/ts/test-mock/storage/message_request_test.ts
index 63d9ea67cf..8347dbbaf3 100644
--- a/ts/test-mock/storage/message_request_test.ts
+++ b/ts/test-mock/storage/message_request_test.ts
@@ -55,11 +55,9 @@ describe('storage service', function needsName() {
     const conversationStack = window.locator('.conversation-stack');
 
     debug('Opening conversation with a stranger');
+    debug(stranger.toContact().uuid);
     await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(stranger.profileName)}]`
-      )
+      .locator(`[data-testid="${stranger.toContact().uuid}"]`)
       .click();
 
     debug("Verify that we stored stranger's profile key");
@@ -124,7 +122,7 @@ describe('storage service', function needsName() {
     const composeArea = window.locator(
       '.composition-area-wrapper, .conversation .ConversationView'
     );
-    const input = composeArea.locator('_react=CompositionInput');
+    const input = composeArea.locator('[data-testid=CompositionInput]');
 
     await input.type('hello stranger!');
     await input.press('Enter');
diff --git a/ts/test-mock/storage/pin_unpin_test.ts b/ts/test-mock/storage/pin_unpin_test.ts
index 5081e70ee6..40007da1bc 100644
--- a/ts/test-mock/storage/pin_unpin_test.ts
+++ b/ts/test-mock/storage/pin_unpin_test.ts
@@ -43,13 +43,7 @@ describe('storage service', function needsName() {
     const conversationStack = window.locator('.conversation-stack');
 
     debug('Verifying that the group is pinned on startup');
-    await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          '[isPinned = true] ' +
-          `[title = ${JSON.stringify(group.title)}]`
-      )
-      .waitFor();
+    await leftPane.locator(`[data-testid="${group.id}"]`).waitFor();
 
     debug('Unpinning group via storage service');
     {
@@ -60,24 +54,14 @@ describe('storage service', function needsName() {
         timestamp: bootstrap.getTimestamp(),
       });
 
-      await leftPane
-        .locator(
-          '_react=ConversationListItem' +
-            '[isPinned = false] ' +
-            `[title = ${JSON.stringify(group.title)}]`
-        )
-        .waitFor();
+      await leftPane.locator(`[data-testid="${group.id}"]`).waitFor();
     }
 
     debug('Pinning group in the app');
     {
       const state = await phone.expectStorageState('consistency check');
 
-      const convo = leftPane.locator(
-        '_react=ConversationListItem' +
-          '[isPinned = false] ' +
-          `[title = ${JSON.stringify(group.title)}]`
-      );
+      const convo = leftPane.locator(`[data-testid="${group.id}"]`);
       await convo.click();
 
       const moreButton = conversationStack.locator(
@@ -120,8 +104,7 @@ describe('storage service', function needsName() {
 
         debug('pinning contact=%d', i);
         const convo = leftPane.locator(
-          '_react=ConversationListItem' +
-            `[title = ${JSON.stringify(contact.profileName)}]`
+          `[data-testid="${contact.toContact().uuid}"]`
         );
         await convo.click();
 
diff --git a/ts/test-mock/storage/sticker_test.ts b/ts/test-mock/storage/sticker_test.ts
index 0e47eb6ee9..327bd49a5e 100644
--- a/ts/test-mock/storage/sticker_test.ts
+++ b/ts/test-mock/storage/sticker_test.ts
@@ -129,10 +129,7 @@ describe('storage service', function needsName() {
     );
 
     await leftPane
-      .locator(
-        '_react=ConversationListItem' +
-          `[title = ${JSON.stringify(firstContact.profileName)}]`
-      )
+      .locator(`[data-testid="${firstContact.toContact().uuid}"]`)
       .click();
 
     {
@@ -235,7 +232,7 @@ describe('storage service', function needsName() {
       .click();
 
     const stickerManager = conversationView.locator(
-      '_react=StickerManagerInner'
+      '[data-testid=StickerManager]'
     );
 
     debug('switching to Installed tab');
@@ -265,10 +262,7 @@ describe('storage service', function needsName() {
 
       debug('waiting for sticker pack to become visible');
       await stickerManager
-        .locator(
-          '_react=StickerManagerPackRowInner' +
-            `[pack.id="${STICKER_PACKS[0].id.toString('hex')}"]`
-        )
+        .locator(`[data-testid="${STICKER_PACKS[0].id.toString('hex')}"]`)
         .waitFor();
     }
 
@@ -285,10 +279,7 @@ describe('storage service', function needsName() {
 
       debug('waiting for sticker pack to become visible');
       await stickerManager
-        .locator(
-          '_react=StickerManagerPackRowInner' +
-            `[pack.id="${STICKER_PACKS[1].id.toString('hex')}"]`
-        )
+        .locator(`[data-testid="${STICKER_PACKS[1].id.toString('hex')}"]`)
         .waitFor();
 
       debug('waiting for storage service update');
diff --git a/ts/textsecure/AccountManager.ts b/ts/textsecure/AccountManager.ts
index f97ad295d3..cf56f6caf5 100644
--- a/ts/textsecure/AccountManager.ts
+++ b/ts/textsecure/AccountManager.ts
@@ -224,7 +224,7 @@ export default class AccountManager extends EventTarget {
           }
           const url = getProvisioningUrl(uuid, pubKey);
 
-          window.CI?.setProvisioningURL(url);
+          window.Signal.CI?.setProvisioningURL(url);
 
           setProvisioningUrl(url);
           request.respond(200, 'OK');
diff --git a/ts/util/StartupQueue.ts b/ts/util/StartupQueue.ts
index caada6b638..79a88984a9 100644
--- a/ts/util/StartupQueue.ts
+++ b/ts/util/StartupQueue.ts
@@ -9,6 +9,8 @@ type EntryType = Readonly<{
   callback(): void;
 }>;
 
+let startupProcessingQueue: StartupQueue | undefined;
+
 export class StartupQueue {
   private readonly map = new Map<string, EntryType>();
 
@@ -38,4 +40,21 @@ export class StartupQueue {
       }
     }
   }
+
+  static initialize(): void {
+    startupProcessingQueue = new StartupQueue();
+  }
+
+  static isReady(): boolean {
+    return Boolean(startupProcessingQueue);
+  }
+
+  static add(id: string, value: number, f: () => void): void {
+    startupProcessingQueue?.add(id, value, f);
+  }
+
+  static flush(): void {
+    startupProcessingQueue?.flush();
+    startupProcessingQueue = undefined;
+  }
 }
diff --git a/ts/util/attachmentDownloadQueue.ts b/ts/util/attachmentDownloadQueue.ts
new file mode 100644
index 0000000000..4deceb145b
--- /dev/null
+++ b/ts/util/attachmentDownloadQueue.ts
@@ -0,0 +1,74 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { MessageAttributesType } from '../model-types.d';
+import type { MessageModel } from '../models/messages';
+import * as log from '../logging/log';
+import { isMoreRecentThan } from './timestamp';
+
+const MAX_ATTACHMENT_DOWNLOAD_AGE = 3600 * 72 * 1000;
+const MAX_ATTACHMENT_MSGS_TO_DOWNLOAD = 250;
+
+let isEnabled = true;
+let attachmentDownloadQueue: Array<MessageModel> | undefined = [];
+
+export function shouldUseAttachmentDownloadQueue(): boolean {
+  return isEnabled;
+}
+
+export function addToAttachmentDownloadQueue(
+  idLog: string,
+  message: MessageModel
+): void {
+  if (!attachmentDownloadQueue) {
+    return;
+  }
+
+  attachmentDownloadQueue.unshift(message);
+
+  log.info(
+    `${idLog}: Adding to attachmentDownloadQueue`,
+    message.get('sent_at')
+  );
+}
+
+export async function flushAttachmentDownloadQueue(): Promise<void> {
+  if (!attachmentDownloadQueue) {
+    return;
+  }
+
+  // NOTE: ts/models/messages.ts expects this global to become undefined
+  // once we stop processing the queue.
+  isEnabled = false;
+
+  const attachmentsToDownload = attachmentDownloadQueue.filter(
+    (message, index) =>
+      index <= MAX_ATTACHMENT_MSGS_TO_DOWNLOAD ||
+      isMoreRecentThan(message.getReceivedAt(), MAX_ATTACHMENT_DOWNLOAD_AGE) ||
+      // Stickers and long text attachments has to be downloaded for UI
+      // to display the message properly.
+      message.hasRequiredAttachmentDownloads()
+  );
+
+  log.info(
+    'Downloading recent attachments of total attachments',
+    attachmentsToDownload.length,
+    attachmentDownloadQueue.length
+  );
+
+  const messagesWithDownloads = await Promise.all(
+    attachmentsToDownload.map(message => message.queueAttachmentDownloads())
+  );
+  const messagesToSave: Array<MessageAttributesType> = [];
+  messagesWithDownloads.forEach((shouldSave, messageKey) => {
+    if (shouldSave) {
+      const message = attachmentsToDownload[messageKey];
+      messagesToSave.push(message.attributes);
+    }
+  });
+  await window.Signal.Data.saveMessages(messagesToSave, {
+    ourUuid: window.storage.user.getCheckedUuid().toString(),
+  });
+
+  attachmentDownloadQueue = undefined;
+}
diff --git a/ts/util/callingPermissions.ts b/ts/util/callingPermissions.ts
index 196922538c..e3490f0324 100644
--- a/ts/util/callingPermissions.ts
+++ b/ts/util/callingPermissions.ts
@@ -2,11 +2,11 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 export async function requestCameraPermissions(): Promise<boolean> {
-  if (!(await window.getMediaCameraPermissions())) {
-    await window.showPermissionsPopup(true, true);
+  if (!(await window.IPC.getMediaCameraPermissions())) {
+    await window.IPC.showPermissionsPopup(true, true);
 
     // Check the setting again (from the source of truth).
-    return window.getMediaCameraPermissions();
+    return window.IPC.getMediaCameraPermissions();
   }
 
   return true;
diff --git a/ts/util/createIPCEvents.ts b/ts/util/createIPCEvents.ts
index 63c1328ccb..36c9513984 100644
--- a/ts/util/createIPCEvents.ts
+++ b/ts/util/createIPCEvents.ts
@@ -308,15 +308,15 @@ export function createIPCEvents(
     getHideMenuBar: () => window.storage.get('hide-menu-bar'),
     setHideMenuBar: value => {
       const promise = window.storage.put('hide-menu-bar', value);
-      window.setAutoHideMenuBar(value);
-      window.setMenuBarVisibility(!value);
+      window.IPC.setAutoHideMenuBar(value);
+      window.IPC.setMenuBarVisibility(!value);
       return promise;
     },
     getSystemTraySetting: () =>
       parseSystemTraySetting(window.storage.get('system-tray-setting')),
     setSystemTraySetting: value => {
       const promise = window.storage.put('system-tray-setting', value);
-      window.updateSystemTraySetting(value);
+      window.IPC.updateSystemTraySetting(value);
       return promise;
     },
 
@@ -361,9 +361,9 @@ export function createIPCEvents(
     setAlwaysRelayCalls: value =>
       window.storage.put('always-relay-calls', value),
 
-    getAutoLaunch: () => window.getAutoLaunch(),
+    getAutoLaunch: () => window.IPC.getAutoLaunch(),
     setAutoLaunch: async (value: boolean) => {
-      return window.setAutoLaunch(value);
+      return window.IPC.setAutoLaunch(value);
     },
 
     isPhoneNumberSharingEnabled: () => isPhoneNumberSharingEnabled(),
@@ -526,8 +526,8 @@ export function createIPCEvents(
       showWhatsNewModal();
     },
 
-    getMediaPermissions: window.getMediaPermissions,
-    getMediaCameraPermissions: window.getMediaCameraPermissions,
+    getMediaPermissions: window.IPC.getMediaPermissions,
+    getMediaCameraPermissions: window.IPC.getMediaCameraPermissions,
 
     persistZoomFactor: zoomFactor =>
       window.storage.put('zoomFactor', zoomFactor),
diff --git a/ts/util/handleRetry.ts b/ts/util/handleRetry.ts
index 5e19117800..3df7b1328a 100644
--- a/ts/util/handleRetry.ts
+++ b/ts/util/handleRetry.ts
@@ -212,7 +212,7 @@ function maybeShowDecryptionToast(
     kind: ToastInternalErrorKind.DecryptionError,
     deviceId,
     name,
-    onShowDebugLog: () => window.showDebugLog(),
+    onShowDebugLog: () => window.IPC.showDebugLog(),
   });
 }
 
diff --git a/ts/util/index.ts b/ts/util/index.ts
index 60a914eeff..deeacf7bbf 100644
--- a/ts/util/index.ts
+++ b/ts/util/index.ts
@@ -38,7 +38,6 @@ import {
   sessionStructureToBytes,
 } from './sessionTranslation';
 import * as zkgroup from './zkgroup';
-import { StartupQueue } from './StartupQueue';
 import { sendToGroup, sendContentMessageToGroup } from './sendToGroup';
 import { RetryPlaceholders } from './retryPlaceholders';
 import * as expirationTimer from './expirationTimer';
@@ -47,7 +46,6 @@ import { MessageController } from './MessageController';
 export {
   GoogleChrome,
   Registration,
-  StartupQueue,
   arrayBufferToObjectURL,
   combineNames,
   createBatcher,
diff --git a/ts/util/requestMicrophonePermissions.ts b/ts/util/requestMicrophonePermissions.ts
index 581627e06f..2545f4b01c 100644
--- a/ts/util/requestMicrophonePermissions.ts
+++ b/ts/util/requestMicrophonePermissions.ts
@@ -4,12 +4,12 @@
 export async function requestMicrophonePermissions(
   forCalling: boolean
 ): Promise<boolean> {
-  const microphonePermission = await window.getMediaPermissions();
+  const microphonePermission = await window.IPC.getMediaPermissions();
   if (!microphonePermission) {
-    await window.showPermissionsPopup(forCalling, false);
+    await window.IPC.showPermissionsPopup(forCalling, false);
 
     // Check the setting again (from the source of truth).
-    return window.getMediaPermissions();
+    return window.IPC.getMediaPermissions();
   }
 
   return true;
diff --git a/ts/shims/showConfirmationDialog.tsx b/ts/util/showConfirmationDialog.tsx
similarity index 69%
rename from ts/shims/showConfirmationDialog.tsx
rename to ts/util/showConfirmationDialog.tsx
index 9528681709..59d1d1bd0f 100644
--- a/ts/shims/showConfirmationDialog.tsx
+++ b/ts/util/showConfirmationDialog.tsx
@@ -1,12 +1,9 @@
 // Copyright 2015 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-// This file is here temporarily while we're switching off of Backbone into
-// React. In the future, and in React-land, please just import and use
-// ConfirmationDialog directly. This is the thin API layer to bridge the gap
-// while we convert things over. Please delete this file once all usages are
-// ported over. Note: this file cannot have any imports/exports since it is
-// being included in a <script /> tag.
+import React from 'react';
+import { render, unmountComponentAtNode } from 'react-dom';
+import { ConfirmationDialog } from '../components/ConfirmationDialog';
 
 type ConfirmationDialogViewProps = {
   onTopOfEverything?: boolean;
@@ -27,7 +24,7 @@ function removeConfirmationDialog() {
     return;
   }
 
-  window.ReactDOM.unmountComponentAtNode(confirmationDialogViewNode);
+  unmountComponentAtNode(confirmationDialogViewNode);
   document.body.removeChild(confirmationDialogViewNode);
 
   if (
@@ -39,7 +36,9 @@ function removeConfirmationDialog() {
   confirmationDialogViewNode = undefined;
 }
 
-function showConfirmationDialog(options: ConfirmationDialogViewProps) {
+export function showConfirmationDialog(
+  options: ConfirmationDialogViewProps
+): void {
   if (confirmationDialogViewNode) {
     removeConfirmationDialog();
   }
@@ -49,9 +48,8 @@ function showConfirmationDialog(options: ConfirmationDialogViewProps) {
 
   confirmationDialogPreviousFocus = document.activeElement as HTMLElement;
 
-  window.ReactDOM.render(
-    // eslint-disable-next-line react/react-in-jsx-scope, react/jsx-no-undef
-    <window.Signal.Components.ConfirmationDialog
+  render(
+    <ConfirmationDialog
       dialogName={options.dialogName}
       onTopOfEverything={options.onTopOfEverything}
       actions={[
@@ -78,5 +76,3 @@ function showConfirmationDialog(options: ConfirmationDialogViewProps) {
     confirmationDialogViewNode
   );
 }
-
-window.showConfirmationDialog = showConfirmationDialog;
diff --git a/ts/window.d.ts b/ts/window.d.ts
index 838a2ffc55..7f645875d6 100644
--- a/ts/window.d.ts
+++ b/ts/window.d.ts
@@ -7,10 +7,8 @@ import type { Store } from 'redux';
 import type * as Backbone from 'backbone';
 import type PQueue from 'p-queue/dist';
 import type { assert } from 'chai';
-import type * as Mustache from 'mustache';
 
 import type { PhoneNumber, PhoneNumberFormat } from 'google-libphonenumber';
-import type { imageToBlurHash } from './util/imageToBlurHash';
 import type * as Util from './util';
 import type {
   ConversationModelCollectionType,
@@ -22,6 +20,7 @@ import type {
   ChallengeHandler,
   IPCRequest as IPCChallengeRequest,
 } from './challenge';
+import type AccountManager from './textsecure/AccountManager';
 import type { WebAPIConnectType } from './textsecure/WebAPI';
 import type { CallingClass } from './services/calling';
 import type * as StorageService from './services/storage';
@@ -37,36 +36,12 @@ import type { ConversationController } from './ConversationController';
 import type { ReduxActions } from './state/types';
 import type { createStore } from './state/createStore';
 import type { createApp } from './state/roots/createApp';
-import type { createSafetyNumberViewer } from './state/roots/createSafetyNumberViewer';
-import type * as appDuck from './state/ducks/app';
-import type * as callingDuck from './state/ducks/calling';
-import type * as conversationsDuck from './state/ducks/conversations';
-import type * as emojisDuck from './state/ducks/emojis';
-import type * as expirationDuck from './state/ducks/expiration';
-import type * as itemsDuck from './state/ducks/items';
-import type * as linkPreviewsDuck from './state/ducks/linkPreviews';
-import type * as networkDuck from './state/ducks/network';
-import type * as updatesDuck from './state/ducks/updates';
-import type * as userDuck from './state/ducks/user';
-import type * as searchDuck from './state/ducks/search';
-import type * as stickersDuck from './state/ducks/stickers';
-import type * as conversationsSelectors from './state/selectors/conversations';
-import type * as searchSelectors from './state/selectors/search';
-import type AccountManager from './textsecure/AccountManager';
 import type Data from './sql/Client';
 import type { MessageModel } from './models/messages';
 import type { ConversationModel } from './models/conversations';
 import type { BatcherType } from './util/batcher';
-import type { AttachmentList } from './components/conversation/AttachmentList';
-import type { ChatColorPicker } from './components/ChatColorPicker';
 import type { ConfirmationDialog } from './components/ConfirmationDialog';
-import type { ContactModal } from './components/conversation/ContactModal';
-import type { MessageDetail } from './components/conversation/MessageDetail';
-import type { Quote } from './components/conversation/Quote';
-import type { StagedLinkPreview } from './components/conversation/StagedLinkPreview';
-import type { DisappearingTimeDialog } from './components/DisappearingTimeDialog';
 import type { SignalProtocolStore } from './SignalProtocolStore';
-import type { StartupQueue } from './util/StartupQueue';
 import type { SocketStatus } from './types/SocketStatus';
 import type SyncRequest from './textsecure/SyncRequest';
 import type { MessageController } from './util/MessageController';
@@ -75,49 +50,49 @@ import type { SystemTraySetting } from './types/SystemTraySetting';
 import type { UUID } from './types/UUID';
 import type { Address } from './types/Address';
 import type { QualifiedAddress } from './types/QualifiedAddress';
-import type { CI } from './CI';
+import type { CIType } from './CI';
 import type { IPCEventsType } from './util/createIPCEvents';
 import type { SignalContextType } from './windows/context';
 import type * as Message2 from './types/Message2';
 import type { initializeMigrations } from './signal';
+import type { WebAudioRecorder } from './WebAudioRecorder';
 
 export { Long } from 'long';
 
-// Synced with the type in ts/shims/showConfirmationDialog
-// we are duplicating it here because that file cannot import/export.
-type ConfirmationDialogViewProps = {
-  dialogName: string;
-  cancelText?: string;
-  confirmStyle?: 'affirmative' | 'negative';
-  message: string;
-  okText: string;
-  reject?: (error: Error) => void;
-  resolve: () => void;
+export type IPCType = {
+  addSetupMenuItems: () => void;
+  closeAbout: () => void;
+  crashReports: {
+    getCount: () => Promise<number>;
+    upload: () => Promise<void>;
+    erase: () => Promise<void>;
+  };
+  drawAttention: () => void;
+  getAutoLaunch: () => Promise<boolean>;
+  getBuiltInImages: () => Promise<Array<string>>;
+  getMediaCameraPermissions: () => Promise<boolean>;
+  getMediaPermissions: () => Promise<boolean>;
+  logAppLoadedEvent?: (options: { processedCount?: number }) => void;
+  readyForUpdates: () => void;
+  removeSetupMenuItems: () => unknown;
+  restart: () => void;
+  setAutoHideMenuBar: (value: boolean) => void;
+  setAutoLaunch: (value: boolean) => Promise<void>;
+  setBadgeCount: (count: number) => void;
+  setMenuBarVisibility: (value: boolean) => void;
+  showDebugLog: () => void;
+  showPermissionsPopup: (
+    forCalling: boolean,
+    forCamera: boolean
+  ) => Promise<void>;
+  showSettings: () => void;
+  showWindow: () => void;
+  shutdown: () => void;
+  titleBarDoubleClick: () => void;
+  updateSystemTraySetting: (value: SystemTraySetting) => void;
+  updateTrayIcon: (count: number) => void;
 };
 
-export declare class WebAudioRecorderClass {
-  constructor(
-    node: GainNode,
-    options: {
-      encoding: string;
-      workerDir: string;
-      options?: { timeLimit?: number };
-    }
-  );
-
-  // Callbacks
-  onComplete?: (recorder: WebAudioRecorderClass, blob: Blob) => unknown;
-  onError?: (recorder: WebAudioRecorderClass, error: Error) => unknown;
-  onTimeout?: () => unknown;
-
-  // Class properties
-  startRecording: () => unknown;
-  finishRecording: () => unknown;
-  isRecording: () => boolean;
-  cancelRecording: () => unknown;
-  worker: Worker;
-}
-
 export type SignalCoreType = {
   Crypto: typeof Crypto;
   Curve: typeof Curve;
@@ -142,43 +117,20 @@ export type SignalCoreType = {
   };
   Util: typeof Util;
   Components: {
-    AttachmentList: typeof AttachmentList;
-    ChatColorPicker: typeof ChatColorPicker;
     ConfirmationDialog: typeof ConfirmationDialog;
-    ContactModal: typeof ContactModal;
-    DisappearingTimeDialog: typeof DisappearingTimeDialog;
-    MessageDetail: typeof MessageDetail;
-    Quote: typeof Quote;
-    StagedLinkPreview: typeof StagedLinkPreview;
   };
   OS: typeof OS;
   State: {
     createStore: typeof createStore;
     Roots: {
       createApp: typeof createApp;
-      createSafetyNumberViewer: typeof createSafetyNumberViewer;
-    };
-    Ducks: {
-      app: typeof appDuck;
-      calling: typeof callingDuck;
-      conversations: typeof conversationsDuck;
-      emojis: typeof emojisDuck;
-      expiration: typeof expirationDuck;
-      items: typeof itemsDuck;
-      linkPreviews: typeof linkPreviewsDuck;
-      network: typeof networkDuck;
-      updates: typeof updatesDuck;
-      user: typeof userDuck;
-      search: typeof searchDuck;
-      stickers: typeof stickersDuck;
-    };
-    Selectors: {
-      conversations: typeof conversationsSelectors;
-      search: typeof searchSelectors;
     };
   };
   conversationControllerStart: () => void;
   challengeHandler?: ChallengeHandler;
+
+  // Test only
+  CI?: CIType;
 };
 
 declare global {
@@ -190,48 +142,12 @@ declare global {
     // Used for sticker creator localization
     localeMessages: { [key: string]: { message: string } };
 
-    // Note: used in background.html, and not type-checked
-    startApp: () => void;
-
-    preloadStartTime: number;
-    preloadEndTime: number;
-
-    removeSetupMenuItems: () => unknown;
-    showPermissionsPopup: (
-      forCalling: boolean,
-      forCamera: boolean
-    ) => Promise<void>;
-
-    FontFace: typeof FontFace;
-    $: typeof jQuery;
-
-    imageToBlurHash: typeof imageToBlurHash;
     isBehindProxy: () => boolean;
-    getAutoLaunch: () => Promise<boolean>;
-    setAutoLaunch: (value: boolean) => Promise<void>;
 
-    Mustache: typeof Mustache;
-    WebAudioRecorder: typeof WebAudioRecorderClass;
-
-    addSetupMenuItems: () => void;
-    attachmentDownloadQueue: Array<MessageModel> | undefined;
-    startupProcessingQueue: StartupQueue | undefined;
-    baseAttachmentsPath: string;
-    baseStickersPath: string;
-    baseTempPath: string;
-    baseDraftPath: string;
-    closeAbout: () => void;
-    crashReports: {
-      getCount: () => Promise<number>;
-      upload: () => Promise<void>;
-      erase: () => Promise<void>;
-    };
-    drawAttention: () => void;
     enterKeyboardMode: () => void;
     enterMouseMode: () => void;
     getAccountManager: () => AccountManager;
     getAppInstance: () => string | undefined;
-    getBuiltInImages: () => Promise<Array<string>>;
     getConversations: () => ConversationModelCollectionType;
     getBuildCreation: () => number;
     getEnvironment: typeof getEnvironment;
@@ -239,8 +155,6 @@ declare global {
     getHostName: () => string;
     getInteractionMode: () => 'mouse' | 'keyboard';
     getLocale: () => string;
-    getMediaCameraPermissions: () => Promise<boolean>;
-    getMediaPermissions: () => Promise<boolean>;
     getServerPublicParams: () => string;
     getSfuUrl: () => string;
     getSocketStatus: () => SocketStatus;
@@ -248,11 +162,8 @@ declare global {
     getTitle: () => string;
     waitForEmptyEventQueue: () => Promise<void>;
     getVersion: () => string;
-    i18n: LocalizerType;
     isAfterVersion: (version: string, anotherVersion: string) => boolean;
     isBeforeVersion: (version: string, anotherVersion: string) => boolean;
-    isFullScreen: () => boolean;
-    isMaximized: () => boolean;
     initialTheme?: ThemeType;
     libphonenumberInstance: {
       parse: (number: string) => PhoneNumber;
@@ -261,66 +172,74 @@ declare global {
     };
     libphonenumberFormat: typeof PhoneNumberFormat;
     nodeSetImmediate: typeof setImmediate;
-    onFullScreenChange: (fullScreen: boolean, maximized: boolean) => void;
     platform: string;
     preloadedImages: Array<HTMLImageElement>;
-    reduxActions: ReduxActions;
-    reduxStore: Store<StateType>;
-    restart: () => void;
     setImmediate: typeof setImmediate;
-    showWindow: () => void;
-    showSettings: () => void;
-    shutdown: () => void;
-    showDebugLog: () => void;
     sendChallengeRequest: (request: IPCChallengeRequest) => void;
-    setAutoHideMenuBar: (value: boolean) => void;
-    setBadgeCount: (count: number) => void;
-    setMenuBarVisibility: (value: boolean) => void;
-    updateSystemTraySetting: (value: SystemTraySetting) => void;
-    showConfirmationDialog: (options: ConfirmationDialogViewProps) => void;
     showKeyboardShortcuts: () => void;
     storage: Storage;
     systemTheme: ThemeType;
-    textsecure: typeof textsecure;
-    titleBarDoubleClick: () => void;
-    updateTrayIcon: (count: number) => void;
-    Backbone: typeof Backbone;
-    CI?: CI;
 
-    Accessibility: {
-      reducedMotionSetting: boolean;
-    };
     Signal: SignalCoreType;
 
+    getServerTrustRoot: () => string;
+    logAuthenticatedConnect?: () => void;
+
+    // ========================================================================
+    // The types below have been somewhat organized. See DESKTOP-4801
+    // ========================================================================
+
+    // Backbone
+    Backbone: typeof Backbone;
+
     ConversationController: ConversationController;
     Events: IPCEventsType;
+    FontFace: typeof FontFace;
     MessageController: MessageController;
     SignalProtocolStore: typeof SignalProtocolStore;
     WebAPI: WebAPIConnectType;
+    WebAudioRecorder: typeof WebAudioRecorder;
     Whisper: WhisperType;
+    getSignalProtocolStore: () => SignalProtocolStore;
+    i18n: LocalizerType;
+    // Note: used in background.html, and not type-checked
+    startApp: () => void;
+    textsecure: typeof textsecure;
 
-    getServerTrustRoot: () => string;
-    readyForUpdates: () => void;
-    logAppLoadedEvent?: (options: { processedCount?: number }) => void;
-    logAuthenticatedConnect?: () => void;
+    // IPC
+    IPC: IPCType;
 
-    // Runtime Flags
-    isShowingModal?: boolean;
+    // State
+    reduxActions: ReduxActions;
+    reduxStore: Store<StateType>;
 
     // Feature Flags
-    GV2_ENABLE_SINGLE_CHANGE_PROCESSING: boolean;
-    GV2_ENABLE_CHANGE_PROCESSING: boolean;
-    GV2_ENABLE_STATE_PROCESSING: boolean;
-    GV2_ENABLE_PRE_JOIN_FETCH: boolean;
-    GV2_MIGRATION_DISABLE_ADD: boolean;
-    GV2_MIGRATION_DISABLE_INVITE: boolean;
+    Flags: {
+      GV2_ENABLE_SINGLE_CHANGE_PROCESSING: boolean;
+      GV2_ENABLE_CHANGE_PROCESSING: boolean;
+      GV2_ENABLE_STATE_PROCESSING: boolean;
+      GV2_ENABLE_PRE_JOIN_FETCH: boolean;
+      GV2_MIGRATION_DISABLE_ADD: boolean;
+      GV2_MIGRATION_DISABLE_INVITE: boolean;
+    };
 
-    RETRY_DELAY: boolean;
+    // Paths
+    BasePaths: {
+      attachments: string;
+      draft: string;
+      stickers: string;
+      temp: string;
+    };
 
-    // Context Isolation
+    // TODO DESKTOP-4801
     SignalContext: SignalContextType;
 
+    // Used only in preload to calculate load time
+    preloadStartTime: number;
+    preloadEndTime: number;
+
     // Test only
+    RETRY_DELAY: boolean;
     assert: typeof assert;
     testUtilities: {
       onComplete: (info: unknown) => void;
diff --git a/ts/windows/main/phase1-ipc.ts b/ts/windows/main/phase1-ipc.ts
index 7865bbd777..2e7890a9e2 100644
--- a/ts/windows/main/phase1-ipc.ts
+++ b/ts/windows/main/phase1-ipc.ts
@@ -3,8 +3,9 @@
 
 import { ipcRenderer as ipc } from 'electron';
 import * as semver from 'semver';
-import { mapValues, noop } from 'lodash';
+import { mapValues } from 'lodash';
 
+import type { IPCType } from '../../window.d';
 import { parseIntWithFallback } from '../../util/parseIntWithFallback';
 import { UUIDKind } from '../../types/UUID';
 import { ThemeType } from '../../types/Util';
@@ -22,13 +23,16 @@ window.i18n = SignalContext.i18n;
 const { config } = window.SignalContext;
 
 // Flags for testing
-window.GV2_ENABLE_SINGLE_CHANGE_PROCESSING = true;
-window.GV2_ENABLE_CHANGE_PROCESSING = true;
-window.GV2_ENABLE_STATE_PROCESSING = true;
-window.GV2_ENABLE_PRE_JOIN_FETCH = true;
+const Flags = {
+  GV2_ENABLE_CHANGE_PROCESSING: true,
+  GV2_ENABLE_PRE_JOIN_FETCH: true,
+  GV2_ENABLE_SINGLE_CHANGE_PROCESSING: true,
+  GV2_ENABLE_STATE_PROCESSING: true,
+  GV2_MIGRATION_DISABLE_ADD: false,
+  GV2_MIGRATION_DISABLE_INVITE: false,
+};
 
-window.GV2_MIGRATION_DISABLE_ADD = false;
-window.GV2_MIGRATION_DISABLE_INVITE = false;
+window.Flags = Flags;
 
 window.RETRY_DELAY = false;
 
@@ -55,9 +59,6 @@ window.getExpiration = () => {
   }
   return localBuildExpiration;
 };
-window.Accessibility = {
-  reducedMotionSetting: Boolean(config.reducedMotionSetting),
-};
 window.getHostName = () => config.hostname;
 window.getServerTrustRoot = () => config.serverTrustRoot;
 window.getServerPublicParams = () => config.serverPublicParams;
@@ -78,13 +79,78 @@ if (config.theme === 'light') {
   window.initialTheme = ThemeType.dark;
 }
 
-window.getAutoLaunch = () => {
-  return ipc.invoke('get-auto-launch');
-};
-window.setAutoLaunch = value => {
-  return ipc.invoke('set-auto-launch', value);
+const IPC: IPCType = {
+  addSetupMenuItems: () => ipc.send('add-setup-menu-items'),
+  closeAbout: () => ipc.send('close-about'),
+  crashReports: {
+    getCount: () => ipc.invoke('crash-reports:get-count'),
+    upload: () => ipc.invoke('crash-reports:upload'),
+    erase: () => ipc.invoke('crash-reports:erase'),
+  },
+  drawAttention: () => {
+    log.info('draw attention');
+    ipc.send('draw-attention');
+  },
+  getAutoLaunch: () => ipc.invoke('get-auto-launch'),
+  getBuiltInImages: () =>
+    new Promise((resolve, reject) => {
+      ipc.once('get-success-built-in-images', (_event, error, value) => {
+        if (error) {
+          return reject(new Error(error));
+        }
+
+        return resolve(value);
+      });
+      ipc.send('get-built-in-images');
+    }),
+  getMediaPermissions: () => ipc.invoke('settings:get:mediaPermissions'),
+  getMediaCameraPermissions: () =>
+    ipc.invoke('settings:get:mediaCameraPermissions'),
+  logAppLoadedEvent: ({ processedCount }) =>
+    ipc.send('signal-app-loaded', {
+      preloadTime: window.preloadEndTime - window.preloadStartTime,
+      connectTime: preloadConnectTime - window.preloadEndTime,
+      processedCount,
+    }),
+  readyForUpdates: () => ipc.send('ready-for-updates'),
+  removeSetupMenuItems: () => ipc.send('remove-setup-menu-items'),
+  restart: () => {
+    log.info('restart');
+    ipc.send('restart');
+  },
+  setAutoHideMenuBar: autoHide => ipc.send('set-auto-hide-menu-bar', autoHide),
+  setAutoLaunch: value => ipc.invoke('set-auto-launch', value),
+  setBadgeCount: count => ipc.send('set-badge-count', count),
+  setMenuBarVisibility: visibility =>
+    ipc.send('set-menu-bar-visibility', visibility),
+  showDebugLog: () => {
+    log.info('showDebugLog');
+    ipc.send('show-debug-log');
+  },
+  showPermissionsPopup: (forCalling, forCamera) =>
+    ipc.invoke('show-permissions-popup', forCalling, forCamera),
+  showSettings: () => ipc.send('show-settings'),
+  showWindow: () => {
+    log.info('show window');
+    ipc.send('show-window');
+  },
+  shutdown: () => {
+    log.info('shutdown');
+    ipc.send('shutdown');
+  },
+  titleBarDoubleClick: () => {
+    ipc.send('title-bar-double-click');
+  },
+  updateSystemTraySetting: (
+    systemTraySetting /* : Readonly<SystemTraySetting> */
+  ) => {
+    void ipc.invoke('update-system-tray-setting', systemTraySetting);
+  },
+  updateTrayIcon: unreadCount => ipc.send('update-tray-icon', unreadCount),
 };
 
+window.IPC = IPC;
+
 window.isBeforeVersion = (toCheck, baseVersion) => {
   try {
     return semver.lt(toCheck, baseVersion);
@@ -108,8 +174,6 @@ window.isAfterVersion = (toCheck, baseVersion) => {
   }
 };
 
-window.setBadgeCount = count => ipc.send('set-badge-count', count);
-
 let preloadConnectTime = 0;
 window.logAuthenticatedConnect = () => {
   if (preloadConnectTime === 0) {
@@ -117,13 +181,6 @@ window.logAuthenticatedConnect = () => {
   }
 };
 
-window.logAppLoadedEvent = ({ processedCount }) =>
-  ipc.send('signal-app-loaded', {
-    preloadTime: window.preloadEndTime - window.preloadStartTime,
-    connectTime: preloadConnectTime - window.preloadEndTime,
-    processedCount,
-  });
-
 // We never do these in our code, so we'll prevent it everywhere
 window.open = () => null;
 
@@ -133,50 +190,6 @@ if (!config.enableCI && config.environment !== 'test') {
   window.eval = global.eval = () => null;
 }
 
-window.drawAttention = () => {
-  log.info('draw attention');
-  ipc.send('draw-attention');
-};
-window.showWindow = () => {
-  log.info('show window');
-  ipc.send('show-window');
-};
-
-window.titleBarDoubleClick = () => {
-  ipc.send('title-bar-double-click');
-};
-
-window.setAutoHideMenuBar = autoHide =>
-  ipc.send('set-auto-hide-menu-bar', autoHide);
-
-window.setMenuBarVisibility = visibility =>
-  ipc.send('set-menu-bar-visibility', visibility);
-
-window.updateSystemTraySetting = (
-  systemTraySetting /* : Readonly<SystemTraySetting> */
-) => {
-  void ipc.invoke('update-system-tray-setting', systemTraySetting);
-};
-
-window.restart = () => {
-  log.info('restart');
-  ipc.send('restart');
-};
-window.shutdown = () => {
-  log.info('shutdown');
-  ipc.send('shutdown');
-};
-window.showDebugLog = () => {
-  log.info('showDebugLog');
-  ipc.send('show-debug-log');
-};
-
-window.closeAbout = () => ipc.send('close-about');
-window.readyForUpdates = () => ipc.send('ready-for-updates');
-
-window.updateTrayIcon = unreadCount =>
-  ipc.send('update-tray-icon', unreadCount);
-
 ipc.on('additional-log-data-request', async event => {
   const ourConversation = window.ConversationController.getOurConversation();
   const ourCapabilities = ourConversation
@@ -238,10 +251,14 @@ ipc.on('power-channel:lock-screen', () => {
 });
 
 ipc.on('window:set-window-stats', (_event, stats) => {
-  if (!window.Whisper.events) {
+  if (!window.reduxActions) {
     return;
   }
-  window.Whisper.events.trigger('setWindowStats', stats);
+
+  window.reduxActions.user.userChanged({
+    isMainWindowMaximized: stats.isMaximized,
+    isMainWindowFullScreen: stats.isFullScreen,
+  });
 });
 
 ipc.on('window:set-menu-options', (_event, options) => {
@@ -253,28 +270,8 @@ ipc.on('window:set-menu-options', (_event, options) => {
 
 window.sendChallengeRequest = request => ipc.send('challenge:request', request);
 
-{
-  let isFullScreen = Boolean(config.isMainWindowFullScreen);
-  let isMaximized = Boolean(config.isMainWindowMaximized);
-
-  window.isFullScreen = () => isFullScreen;
-  window.isMaximized = () => isMaximized;
-  // This is later overwritten.
-  window.onFullScreenChange = noop;
-
-  ipc.on('window:set-window-stats', (_event, stats) => {
-    isFullScreen = Boolean(stats.isFullScreen);
-    isMaximized = Boolean(stats.isMaximized);
-    window.onFullScreenChange(isFullScreen, isMaximized);
-  });
-}
-
 // Settings-related events
 
-window.showSettings = () => ipc.send('show-settings');
-window.showPermissionsPopup = (forCalling, forCamera) =>
-  ipc.invoke('show-permissions-popup', forCalling, forCamera);
-
 ipc.on('show-keyboard-shortcuts', () => {
   window.Events.showKeyboardShortcuts();
 });
@@ -285,18 +282,6 @@ ipc.on('remove-dark-overlay', () => {
   window.Events.removeDarkOverlay();
 });
 
-window.getBuiltInImages = () =>
-  new Promise((resolve, reject) => {
-    ipc.once('get-success-built-in-images', (_event, error, value) => {
-      if (error) {
-        return reject(new Error(error));
-      }
-
-      return resolve(value);
-    });
-    ipc.send('get-built-in-images');
-  });
-
 ipc.on('delete-all-data', async () => {
   const { deleteAllData } = window.Events;
   if (!deleteAllData) {
@@ -373,6 +358,3 @@ ipc.on('show-release-notes', () => {
     showReleaseNotes();
   }
 });
-
-window.addSetupMenuItems = () => ipc.send('add-setup-menu-items');
-window.removeSetupMenuItems = () => ipc.send('remove-setup-menu-items');
diff --git a/ts/windows/main/phase2-dependencies.ts b/ts/windows/main/phase2-dependencies.ts
index a26f7b7daa..e6b7afe957 100644
--- a/ts/windows/main/phase2-dependencies.ts
+++ b/ts/windows/main/phase2-dependencies.ts
@@ -9,7 +9,6 @@ import * as moment from 'moment';
 import 'moment/min/locales.min';
 
 import { textsecure } from '../../textsecure';
-import { imageToBlurHash } from '../../util/imageToBlurHash';
 import * as Attachments from '../attachments';
 import { setup } from '../../signal';
 import { addSensitivePath } from '../../util/privacy';
@@ -38,7 +37,6 @@ window.WebAPI = window.textsecure.WebAPI.initialize({
   version: config.version,
 });
 
-window.imageToBlurHash = imageToBlurHash;
 window.libphonenumberInstance = PhoneNumberUtil.getInstance();
 window.libphonenumberFormat = PhoneNumberFormat;
 
@@ -56,12 +54,14 @@ moment.updateLocale(locale, {
 moment.locale(locale);
 
 const userDataPath = SignalContext.getPath('userData');
-window.baseAttachmentsPath = Attachments.getPath(userDataPath);
-window.baseStickersPath = Attachments.getStickersPath(userDataPath);
-window.baseTempPath = Attachments.getTempPath(userDataPath);
-window.baseDraftPath = Attachments.getDraftPath(userDataPath);
+window.BasePaths = {
+  attachments: Attachments.getPath(userDataPath),
+  draft: Attachments.getDraftPath(userDataPath),
+  stickers: Attachments.getStickersPath(userDataPath),
+  temp: Attachments.getTempPath(userDataPath),
+};
 
-addSensitivePath(window.baseAttachmentsPath);
+addSensitivePath(window.BasePaths.attachments);
 if (config.crashDumpsPath) {
   addSensitivePath(config.crashDumpsPath);
 }
diff --git a/ts/windows/main/phase4-test.ts b/ts/windows/main/phase4-test.ts
index 008945e03e..3d5cba0f5a 100644
--- a/ts/windows/main/phase4-test.ts
+++ b/ts/windows/main/phase4-test.ts
@@ -13,6 +13,6 @@ if (config.environment === 'test') {
 }
 if (config.enableCI) {
   console.log('Importing CI infrastructure...');
-  const { CI } = require('../../CI');
-  window.CI = new CI(window.getTitle());
+  const { getCI } = require('../../CI');
+  window.Signal.CI = getCI(window.getTitle());
 }
diff --git a/ts/windows/main/start.ts b/ts/windows/main/start.ts
index 2bcb261fb8..2e913884a7 100644
--- a/ts/windows/main/start.ts
+++ b/ts/windows/main/start.ts
@@ -1,13 +1,23 @@
 // Copyright 2017 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
+import { clone } from 'lodash';
+import { contextBridge } from 'electron';
+
 import * as log from '../../logging/log';
+import { SignalContext } from '../context';
 
 import './phase1-ipc';
 import '../preload';
 import './phase2-dependencies';
 import './phase3-post-signal';
 import './phase4-test';
+import '../../backbone/reliable_trigger';
+
+import { WebAudioRecorder } from '../../WebAudioRecorder';
+import { getSignalProtocolStore } from '../../SignalProtocolStore';
+import { start as startConversationController } from '../../ConversationController';
+import { MessageController } from '../../util/MessageController';
 
 window.addEventListener('contextmenu', e => {
   const node = e.target as Element | null;
@@ -27,3 +37,122 @@ window.addEventListener('contextmenu', e => {
 if (window.SignalContext.config.proxyUrl) {
   log.info('Using provided proxy url');
 }
+
+const isTestElectron = process.env.TEST_QUIT_ON_COMPLETE;
+
+window.Whisper.events = clone(window.Backbone.Events);
+MessageController.install();
+startConversationController();
+
+if (isTestElectron) {
+  window.getSignalProtocolStore = getSignalProtocolStore;
+} else {
+  contextBridge.exposeInMainWorld('SignalContext', SignalContext);
+
+  contextBridge.exposeInMainWorld('Backbone', window.Backbone);
+
+  contextBridge.exposeInMainWorld('BasePaths', window.BasePaths);
+  contextBridge.exposeInMainWorld(
+    'ConversationController',
+    window.ConversationController
+  );
+  contextBridge.exposeInMainWorld('Events', window.Events);
+  contextBridge.exposeInMainWorld('Flags', window.Flags);
+  contextBridge.exposeInMainWorld('IPC', window.IPC);
+  contextBridge.exposeInMainWorld(
+    'SignalProtocolStore',
+    window.SignalProtocolStore
+  );
+  contextBridge.exposeInMainWorld(
+    'getSignalProtocolStore',
+    getSignalProtocolStore
+  );
+  contextBridge.exposeInMainWorld(
+    'MessageController',
+    window.MessageController
+  );
+  contextBridge.exposeInMainWorld('WebAudioRecorder', WebAudioRecorder);
+  contextBridge.exposeInMainWorld('WebAPI', window.WebAPI);
+  contextBridge.exposeInMainWorld('Whisper', window.Whisper);
+  contextBridge.exposeInMainWorld('i18n', window.i18n);
+  contextBridge.exposeInMainWorld('reduxActions', window.reduxActions);
+  contextBridge.exposeInMainWorld('reduxStore', window.reduxStore);
+  contextBridge.exposeInMainWorld('startApp', window.startApp);
+  contextBridge.exposeInMainWorld('textsecure', window.textsecure);
+
+  // TODO DESKTOP-4801
+  contextBridge.exposeInMainWorld('ROOT_PATH', window.ROOT_PATH);
+  contextBridge.exposeInMainWorld('Signal', window.Signal);
+  contextBridge.exposeInMainWorld(
+    'enterKeyboardMode',
+    window.enterKeyboardMode
+  );
+  contextBridge.exposeInMainWorld('enterMouseMode', window.enterMouseMode);
+  contextBridge.exposeInMainWorld(
+    'getAccountManager',
+    window.getAccountManager
+  );
+  contextBridge.exposeInMainWorld('getAppInstance', window.getAppInstance);
+  contextBridge.exposeInMainWorld('getBuildCreation', window.getBuildCreation);
+  contextBridge.exposeInMainWorld('getConversations', window.getConversations);
+  contextBridge.exposeInMainWorld('getEnvironment', window.getEnvironment);
+  contextBridge.exposeInMainWorld('getExpiration', window.getExpiration);
+  contextBridge.exposeInMainWorld('getHostName', window.getHostName);
+  contextBridge.exposeInMainWorld(
+    'getInteractionMode',
+    window.getInteractionMode
+  );
+  contextBridge.exposeInMainWorld('getLocale', window.getLocale);
+  contextBridge.exposeInMainWorld(
+    'getServerPublicParams',
+    window.getServerPublicParams
+  );
+  contextBridge.exposeInMainWorld(
+    'getServerTrustRoot',
+    window.getServerTrustRoot
+  );
+  contextBridge.exposeInMainWorld('getSfuUrl', window.getSfuUrl);
+  contextBridge.exposeInMainWorld('getSocketStatus', window.getSocketStatus);
+  contextBridge.exposeInMainWorld('getSyncRequest', window.getSyncRequest);
+  contextBridge.exposeInMainWorld('getTitle', window.getTitle);
+  contextBridge.exposeInMainWorld('getVersion', window.getVersion);
+  contextBridge.exposeInMainWorld('initialTheme', window.initialTheme);
+  contextBridge.exposeInMainWorld('isAfterVersion', window.isAfterVersion);
+  contextBridge.exposeInMainWorld('isBeforeVersion', window.isBeforeVersion);
+  contextBridge.exposeInMainWorld('isBehindProxy', window.isBehindProxy);
+  contextBridge.exposeInMainWorld(
+    'libphonenumberFormat',
+    window.libphonenumberFormat
+  );
+  contextBridge.exposeInMainWorld(
+    'libphonenumberInstance',
+    window.libphonenumberInstance
+  );
+  contextBridge.exposeInMainWorld('localeMessages', window.localeMessages);
+  contextBridge.exposeInMainWorld(
+    'logAuthenticatedConnect',
+    window.logAuthenticatedConnect
+  );
+  contextBridge.exposeInMainWorld('nodeSetImmediate', window.nodeSetImmediate);
+  contextBridge.exposeInMainWorld('platform', window.platform);
+  contextBridge.exposeInMainWorld('preloadedImages', window.preloadedImages);
+  contextBridge.exposeInMainWorld(
+    'sendChallengeRequest',
+    window.sendChallengeRequest
+  );
+  contextBridge.exposeInMainWorld('setImmediate', window.setImmediate);
+  contextBridge.exposeInMainWorld(
+    'showKeyboardShortcuts',
+    window.showKeyboardShortcuts
+  );
+  contextBridge.exposeInMainWorld('storage', window.storage);
+  contextBridge.exposeInMainWorld('systemTheme', window.systemTheme);
+  contextBridge.exposeInMainWorld(
+    'waitForEmptyEventQueue',
+    window.waitForEmptyEventQueue
+  );
+
+  contextBridge.exposeInMainWorld('assert', window.assert);
+  contextBridge.exposeInMainWorld('RETRY_DELAY', window.RETRY_DELAY);
+  contextBridge.exposeInMainWorld('testUtilities', window.testUtilities);
+}
diff --git a/ts/windows/preload.ts b/ts/windows/preload.ts
index 2832a31174..b17e2e8a46 100644
--- a/ts/windows/preload.ts
+++ b/ts/windows/preload.ts
@@ -1,8 +1,6 @@
 // Copyright 2017 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-import { ipcRenderer as ipc } from 'electron';
-
 import { installCallback, installSetting } from '../util/preload';
 
 // ChatColorPicker redux hookups
@@ -71,14 +69,3 @@ installCallback('getAvailableIODevices');
 installSetting('preferredAudioInputDevice');
 installSetting('preferredAudioOutputDevice');
 installSetting('preferredVideoInputDevice');
-
-window.getMediaPermissions = () => ipc.invoke('settings:get:mediaPermissions');
-
-window.getMediaCameraPermissions = () =>
-  ipc.invoke('settings:get:mediaCameraPermissions');
-
-window.crashReports = {
-  getCount: () => ipc.invoke('crash-reports:get-count'),
-  upload: () => ipc.invoke('crash-reports:upload'),
-  erase: () => ipc.invoke('crash-reports:erase'),
-};
diff --git a/yarn.lock b/yarn.lock
index 6e5f6cfbf1..0717d0afad 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2178,10 +2178,10 @@
     node-gyp-build "^4.2.3"
     uuid "^8.3.0"
 
-"@signalapp/mock-server@2.12.0":
-  version "2.12.0"
-  resolved "https://registry.yarnpkg.com/@signalapp/mock-server/-/mock-server-2.12.0.tgz#ca7ed46406603746d2cb49349d3fb843fe4b45eb"
-  integrity sha512-d6OFulnOWG0U3Xj0ChBGHThyBlno54Va+Cb/E0ggEx7PhD1Y9GX8gLc0V8HHP203b+1JThX4SdK03dpsOILxfQ==
+"@signalapp/mock-server@2.12.1":
+  version "2.12.1"
+  resolved "https://registry.yarnpkg.com/@signalapp/mock-server/-/mock-server-2.12.1.tgz#456ee3c9458363d333bd803910f874d388f28d04"
+  integrity sha512-c8ndwTtDoRPRZAWjbBeVH79DQLA4UvKPztgJUqtDOqFCju1+NMKbjxrK+v1PJQvhhOMANbG6Z3qTCl4UGcm/zQ==
   dependencies:
     "@signalapp/libsignal-client" "^0.20.0"
     debug "^4.3.2"
@@ -4032,11 +4032,6 @@
   resolved "https://registry.yarnpkg.com/@types/ms/-/ms-0.7.31.tgz#31b7ca6407128a3d2bbc27fe2d21b345397f6197"
   integrity sha512-iiUgKzV9AuaEkZqkOLDIvlQiL6ltuZd9tGcW3gwpnX8JbuiuhFlEGmmFXEXkN50Cvq7Os88IY2v0dkDqXYWVgA==
 
-"@types/mustache@4.1.2":
-  version "4.1.2"
-  resolved "https://registry.yarnpkg.com/@types/mustache/-/mustache-4.1.2.tgz#d0e158013c81674a5b6d8780bc3fe234e1804eaf"
-  integrity sha512-c4OVMMcyodKQ9dpwBwh3ofK9P6U9ZktKU9S+p33UqwMNN1vlv2P0zJZUScTshnx7OEoIIRcCFNQ904sYxZz8kg==
-
 "@types/node-fetch@2.6.2":
   version "2.6.2"
   resolved "https://registry.yarnpkg.com/@types/node-fetch/-/node-fetch-2.6.2.tgz#d1a9c5fd049d9415dce61571557104dec3ec81da"