diff --git a/extensions/markdown-language-features/notebook/index.ts b/extensions/markdown-language-features/notebook/index.ts
index cecde581a9f..5ae7c219763 100644
--- a/extensions/markdown-language-features/notebook/index.ts
+++ b/extensions/markdown-language-features/notebook/index.ts
@@ -12,7 +12,7 @@ export function activate() {
 
 	return {
 		renderCell: (_id: string, context: { element: HTMLElement, value: string, text(): string }) => {
-			const rendered = markdownIt.render(context.value || context.text()); // todo@jrieken remove .value-usage
+			const rendered = markdownIt.render(context.text());
 			context.element.innerHTML = rendered;
 
 			// Insert styles into markdown preview shadow dom so that they are applied
diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
index 98b9ac8c12b..793dc37db5f 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/notebook.test.ts
@@ -56,7 +56,7 @@ class Kernel {
 	}
 
 	protected async _runCell(cell: vscode.NotebookCell) {
-		const task = this.controller.createNotebookCellExecutionTask(cell);
+		const task = this.controller.createNotebookCellExecution(cell);
 		task.start();
 		task.executionOrder = 1;
 		if (cell.notebook.uri.path.endsWith('customRenderer.vsctestnb')) {
@@ -180,7 +180,7 @@ suite('Notebook API tests', function () {
 			}
 
 			override async _runCell(cell: vscode.NotebookCell) {
-				const task = this.controller.createNotebookCellExecutionTask(cell);
+				const task = this.controller.createNotebookCellExecution(cell);
 				task.start();
 				await task.replaceOutput([new vscode.NotebookCellOutput([
 					vscode.NotebookCellOutputItem.text('my second output', 'text/plain', undefined)
@@ -772,7 +772,7 @@ suite('Notebook API tests', function () {
 
 			override async _execute(cells: vscode.NotebookCell[]) {
 				for (const cell of cells) {
-					const task = this.controller.createNotebookCellExecutionTask(cell);
+					const task = this.controller.createNotebookCellExecution(cell);
 					task.start();
 					task.token.onCancellationRequested(async () => {
 						await task.replaceOutput([new vscode.NotebookCellOutput([
@@ -812,10 +812,10 @@ suite('Notebook API tests', function () {
 				this.controller.interruptHandler = this.interrupt.bind(this);
 			}
 
-			private _task: vscode.NotebookCellExecutionTask | undefined;
+			private _task: vscode.NotebookCellExecution | undefined;
 
 			override async _execute(cells: vscode.NotebookCell[]) {
-				this._task = this.controller.createNotebookCellExecutionTask(cells[0]);
+				this._task = this.controller.createNotebookCellExecution(cells[0]);
 				this._task.start();
 			}
 
@@ -1178,7 +1178,7 @@ suite('Notebook API tests', function () {
 
 			override async _execute(cells: vscode.NotebookCell[]) {
 				const [cell] = cells;
-				const task = this.controller.createNotebookCellExecutionTask(cell);
+				const task = this.controller.createNotebookCellExecution(cell);
 				task.start();
 				await task.replaceOutput([new vscode.NotebookCellOutput([
 					vscode.NotebookCellOutputItem.text('Some output', 'text/plain', undefined)
diff --git a/extensions/vscode-notebook-tests/src/extension.ts b/extensions/vscode-notebook-tests/src/extension.ts
index 935968c0b4e..ae4fb948438 100644
--- a/extensions/vscode-notebook-tests/src/extension.ts
+++ b/extensions/vscode-notebook-tests/src/extension.ts
@@ -66,7 +66,7 @@ export function activate(context: vscode.ExtensionContext): any {
 
 	controller.executeHandler = (cells) => {
 		for (const cell of cells) {
-			const task = controller.createNotebookCellExecutionTask(cell);
+			const task = controller.createNotebookCellExecution(cell);
 			task.start();
 			task.replaceOutput([new vscode.NotebookCellOutput([
 				vscode.NotebookCellOutputItem.text('test output', 'text/html', undefined)
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index a9c410a5bd4..b1f98b56245 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -1316,11 +1316,6 @@ declare module 'vscode' {
 		 */
 		data: Uint8Array;
 
-		/**
-		 * @deprecated
-		 */
-		value: unknown;
-
 		//todo@API
 		metadata?: { [key: string]: any };
 
@@ -1508,31 +1503,25 @@ declare module 'vscode' {
 		(this: NotebookController, cells: NotebookCell[], notebook: NotebookDocument, controller: NotebookController): void | Thenable<void>
 	}
 
-	export interface NotebookInterruptHandler {
-		/**
-		 * @param notebook The notebook for which the interrupt handler is being called.
-		 */
-		(this: NotebookController, notebook: NotebookDocument): void | Thenable<void>;
-	}
-
 	export enum NotebookControllerAffinity {
 		Default = 1,
 		Preferred = 2
 	}
 
-	// todo@API this is called Controller
-	export class NotebookKernelPreload {
+
+	export class NotebookRendererScript {
+
 		/**
 		 * APIs that the preload provides to the renderer. These are matched
 		 * against the `dependencies` and `optionalDependencies` arrays in the
 		 * notebook renderer contribution point.
 		 */
-		readonly provides: string[];
+		provides: string[];
 
 		/**
 		 * URI for the file to preload
 		 */
-		readonly uri: Uri;
+		uri: Uri;
 
 		/**
 		 * @param uri URI for the file to preload
@@ -1562,31 +1551,53 @@ declare module 'vscode' {
 		endTime?: number;
 	}
 
-	// todo@API jsdoc slightly outdated: kernel, notebook.createNotebookCellExecutionTask
+	// todo@API jsdoc slightly outdated: kernel, notebook.createNotebookCellExecution
 	/**
-	 * A NotebookCellExecutionTask is how the kernel modifies a notebook cell as it is executing. When
-	 * {@link notebook.createNotebookCellExecutionTask `createNotebookCellExecutionTask`} is called, the cell
+	 * A NotebookCellExecution is how the kernel modifies a notebook cell as it is executing. When
+	 * {@link notebook.createNotebookCellExecution `createNotebookCellExecution`} is called, the cell
 	 * enters the Pending state. When `start()` is called on the execution task, it enters the Executing state. When
 	 * `end()` is called, it enters the Idle state. While in the Executing state, cell outputs can be
 	 * modified with the methods on the run task.
 	 *
-	 * All outputs methods operate on this NotebookCellExecutionTask's cell by default. They optionally take
+	 * All outputs methods operate on this NotebookCellExecution's cell by default. They optionally take
 	 * a cellIndex parameter that allows them to modify the outputs of other cells. `appendOutputItems` and
 	 * `replaceOutputItems` operate on the output with the given ID, which can be an output on any cell. They
 	 * all resolve once the output edit has been applied.
 	 */
-	export interface NotebookCellExecutionTask {
-		readonly document: NotebookDocument;
+	export interface NotebookCellExecution {
+
+		/**
+		 * The {@link NotebookCell cell} for which this execution has been created.
+		 */
 		readonly cell: NotebookCell;
+
+		/**
+		 * A cancellation token which will be triggered when the cell execution is canceled
+		 * from the UI.
+		 *
+		 * _Note_ that the cancellation token will not be triggered when the {@link NotebookController controller}
+		 * that created this execution uses an {@link NotebookController.interruptHandler interrupt-handler}.
+		 */
 		readonly token: CancellationToken;
 
-		start(context?: NotebookCellExecuteStartContext): void;
+		//todo@API remove? use cell.notebook instead?
+		readonly document: NotebookDocument;
+
+		/**
+		 * Set and unset the order of this cell execution.
+		 */
 		executionOrder: number | undefined;
+
+		// todo@API inline context object?
+		start(context?: NotebookCellExecuteStartContext): void;
+		// todo@API inline context object?
 		end(result?: NotebookCellExecuteEndContext): void;
 
+		// todo@API use object instead of index? FF
 		clearOutput(cellIndex?: number): Thenable<void>;
 		appendOutput(out: NotebookCellOutput | NotebookCellOutput[], cellIndex?: number): Thenable<void>;
 		replaceOutput(out: NotebookCellOutput | NotebookCellOutput[], cellIndex?: number): Thenable<void>;
+		// todo@API use object instead of index?
 		appendOutputItems(items: NotebookCellOutputItem | NotebookCellOutputItem[], outputId: string): Thenable<void>;
 		replaceOutputItems(items: NotebookCellOutputItem | NotebookCellOutputItem[], outputId: string): Thenable<void>;
 	}
@@ -1647,16 +1658,23 @@ declare module 'vscode' {
 
 		/**
 		 * The execute handler is invoked when the run gestures in the UI are selected, e.g Run Cell, Run All,
-		 * Run Selection etc.
+		 * Run Selection etc. The execute handler is responsible for creating and managing {@link NotebookCellExecution execution}-objects.
 		 */
 		executeHandler: NotebookExecuteHandler;
 
 		/**
-		 * The interrupt handler is invoked the interrupt all execution. This is contrary to cancellation (available via
-		 * [`NotebookCellExecutionTask#token`](NotebookCellExecutionTask#token)) and should only be used when
-		 * execution-level cancellation is supported
+		 * Optional interrupt handler.
+		 *
+		 * By default cell execution is canceled via {@link NotebookCellExecution.token tokens}. Cancellation
+		 * tokens require that a controller can keep track of its execution so that it can cancel a specific execution at a later
+		 * point. Not all scenarios allow for that, eg. REPL-style controllers often work by interrupting whatever is currently
+		 * running. For those cases the {@link NotebookInterruptHandler interrupt handler} exists - it can be thought of as the
+		 * equivalent of `SIGINT` or `Control+C` in terminals.
+		 *
+		 * _Note_ that supporting {@link NotebookCellExecution.token cancellation tokens} is preferred and that interrupt handlers should
+		 * only be used when tokens cannot be supported.
 		 */
-		interruptHandler?: NotebookInterruptHandler
+		interruptHandler?: (this: NotebookController, notebook: NotebookDocument) => void | Thenable<void>;
 
 		/**
 		 * Dispose and free associated resources.
@@ -1689,13 +1707,10 @@ declare module 'vscode' {
 		 * @param cell The notebook cell for which to create the execution.
 		 * @returns A notebook cell execution.
 		 */
-		// todo@API rename to NotebookCellExecution
-		createNotebookCellExecutionTask(cell: NotebookCell): NotebookCellExecutionTask;
+		createNotebookCellExecution(cell: NotebookCell): NotebookCellExecution;
 
-		// todo@API find a better name than "preloads"
 		// todo@API allow add, not remove
-		// ipc
-		readonly preloads: NotebookKernelPreload[];
+		readonly rendererScripts: NotebookRendererScript[];
 
 		/**
 		 * An event that fires when a renderer (see `preloads`) has send a message to the controller.
@@ -1840,9 +1855,9 @@ declare module 'vscode' {
 		 * @param viewType A notebook view type for which this controller is for.
 		 * @param label The label of the controller
 		 * @param handler
-		 * @param preloads
+		 * @param rendererScripts
 		 */
-		export function createNotebookController(id: string, viewType: string, label: string, handler?: NotebookExecuteHandler, preloads?: NotebookKernelPreload[]): NotebookController;
+		export function createNotebookController(id: string, viewType: string, label: string, handler?: NotebookExecuteHandler, rendererScripts?: NotebookRendererScript[]): NotebookController;
 
 		// todo@API what is this used for?
 		// todo@API qualify cell, ...NotebookCell...
diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index f1e5df0ebbd..24ec26272fa 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -1275,7 +1275,7 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			NotebookCellMetadata: extHostTypes.NotebookCellMetadata,
 			NotebookCellData: extHostTypes.NotebookCellData,
 			NotebookData: extHostTypes.NotebookData,
-			NotebookKernelPreload: extHostTypes.NotebookKernelPreload,
+			NotebookRendererScript: extHostTypes.NotebookRendererScript,
 			NotebookCellStatusBarAlignment: extHostTypes.NotebookCellStatusBarAlignment,
 			NotebookEditorRevealType: extHostTypes.NotebookEditorRevealType,
 			NotebookCellOutput: extHostTypes.NotebookCellOutput,
diff --git a/src/vs/workbench/api/common/extHostNotebookKernels.ts b/src/vs/workbench/api/common/extHostNotebookKernels.ts
index 2464bd06ad7..9cf31f438e7 100644
--- a/src/vs/workbench/api/common/extHostNotebookKernels.ts
+++ b/src/vs/workbench/api/common/extHostNotebookKernels.ts
@@ -26,7 +26,7 @@ interface IKernelData {
 	extensionId: ExtensionIdentifier,
 	controller: vscode.NotebookController;
 	onDidChangeSelection: Emitter<{ selected: boolean; notebook: vscode.NotebookDocument; }>;
-	onDidReceiveMessage: Emitter<{ editor: vscode.NotebookEditor, message: any }>;
+	onDidReceiveMessage: Emitter<{ editor: vscode.NotebookEditor, message: any; }>;
 	associatedNotebooks: ResourceMap<boolean>;
 }
 
@@ -47,7 +47,7 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 		this._proxy = _mainContext.getProxy(MainContext.MainThreadNotebookKernels);
 	}
 
-	createNotebookController(extension: IExtensionDescription, id: string, viewType: string, label: string, handler?: vscode.NotebookExecuteHandler, preloads?: vscode.NotebookKernelPreload[]): vscode.NotebookController {
+	createNotebookController(extension: IExtensionDescription, id: string, viewType: string, label: string, handler?: vscode.NotebookExecuteHandler, preloads?: vscode.NotebookRendererScript[]): vscode.NotebookController {
 
 		for (let data of this._kernelData.values()) {
 			if (data.controller.id === id && ExtensionIdentifier.equals(extension.identifier, data.extensionId)) {
@@ -66,8 +66,8 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 		let isDisposed = false;
 		const commandDisposables = new DisposableStore();
 
-		const onDidChangeSelection = new Emitter<{ selected: boolean, notebook: vscode.NotebookDocument }>();
-		const onDidReceiveMessage = new Emitter<{ editor: vscode.NotebookEditor, message: any }>();
+		const onDidChangeSelection = new Emitter<{ selected: boolean, notebook: vscode.NotebookDocument; }>();
+		const onDidReceiveMessage = new Emitter<{ editor: vscode.NotebookEditor, message: any; }>();
 
 		const data: INotebookKernelDto2 = {
 			id: `${extension.identifier.value}/${id}`,
@@ -75,12 +75,12 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 			extensionId: extension.identifier,
 			extensionLocation: extension.extensionLocation,
 			label: label || extension.identifier.value,
-			preloads: preloads ? preloads.map(extHostTypeConverters.NotebookKernelPreload.from) : []
+			preloads: preloads ? preloads.map(extHostTypeConverters.NotebookRendererScript.from) : []
 		};
 
 		//
 		let _executeHandler: vscode.NotebookExecuteHandler = handler ?? _defaultExecutHandler;
-		let _interruptHandler: vscode.NotebookInterruptHandler | undefined;
+		let _interruptHandler: ((this: vscode.NotebookController, notebook: vscode.NotebookDocument) => void | Thenable<void>) | undefined;
 
 		// todo@jrieken the selector needs to be massaged
 		this._proxy.$addKernel(handle, data).catch(err => {
@@ -147,8 +147,8 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 				data.hasExecutionOrder = value;
 				_update();
 			},
-			get preloads() {
-				return data.preloads ? data.preloads.map(extHostTypeConverters.NotebookKernelPreload.to) : [];
+			get rendererScripts() {
+				return data.preloads ? data.preloads.map(extHostTypeConverters.NotebookRendererScript.to) : [];
 			},
 			get executeHandler() {
 				return _executeHandler;
@@ -164,7 +164,7 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 				data.supportsInterrupt = Boolean(value);
 				_update();
 			},
-			createNotebookCellExecutionTask(cell) {
+			createNotebookCellExecution(cell) {
 				if (isDisposed) {
 					throw new Error('notebook controller is DISPOSED');
 				}
@@ -259,16 +259,19 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 			// extension can dispose kernels in the meantime
 			return;
 		}
+
+		// cancel or interrupt depends on the controller. When an interrupt handler is used we
+		// don't trigger the cancelation token of executions.
 		const document = this._extHostNotebook.getNotebookDocument(URI.revive(uri));
 		if (obj.controller.interruptHandler) {
 			await obj.controller.interruptHandler.call(obj.controller, document.apiNotebook);
-		}
 
-		// we do both? interrupt and cancellation or should we be selective?
-		for (let cellHandle of handles) {
-			const cell = document.getCell(cellHandle);
-			if (cell) {
-				this._activeExecutions.get(cell.uri)?.cancel();
+		} else {
+			for (let cellHandle of handles) {
+				const cell = document.getCell(cellHandle);
+				if (cell) {
+					this._activeExecutions.get(cell.uri)?.cancel();
+				}
 			}
 		}
 	}
@@ -290,7 +293,7 @@ export class ExtHostNotebookKernels implements ExtHostNotebookKernelsShape {
 
 	// ---
 
-	_createNotebookCellExecution(cell: vscode.NotebookCell): vscode.NotebookCellExecutionTask {
+	_createNotebookCellExecution(cell: vscode.NotebookCell): vscode.NotebookCellExecution {
 		if (cell.index < 0) {
 			throw new Error('CANNOT execute cell that has been REMOVED from notebook');
 		}
@@ -403,9 +406,9 @@ class NotebookCellExecutionTask extends Disposable {
 		});
 	}
 
-	asApiObject(): vscode.NotebookCellExecutionTask {
+	asApiObject(): vscode.NotebookCellExecution {
 		const that = this;
-		return Object.freeze(<vscode.NotebookCellExecutionTask>{
+		return Object.freeze(<vscode.NotebookCellExecution>{
 			get token() { return that._tokenSource.token; },
 			get document() { return that._document.apiNotebook; },
 			get cell() { return that._cell.apiCell; },
diff --git a/src/vs/workbench/api/common/extHostTypeConverters.ts b/src/vs/workbench/api/common/extHostTypeConverters.ts
index 9cb1fd3f72f..2b011cbb0f0 100644
--- a/src/vs/workbench/api/common/extHostTypeConverters.ts
+++ b/src/vs/workbench/api/common/extHostTypeConverters.ts
@@ -1534,30 +1534,15 @@ export namespace NotebookCellData {
 
 export namespace NotebookCellOutputItem {
 	export function from(item: types.NotebookCellOutputItem): notebooks.IOutputItemDto {
-		let value: unknown;
-		let valueBytes: number[] | undefined;
-		if (item.data instanceof Uint8Array) {
-			//todo@jrieken this HACKY and SLOW... hoist VSBuffer instead
-			valueBytes = Array.from(item.data);
-		} else {
-			value = item.value;
-		}
 		return {
 			metadata: item.metadata,
 			mime: item.mime,
-			value,
-			valueBytes,
+			valueBytes: Array.from(item.data), //todo@jrieken this HACKY and SLOW... hoist VSBuffer instead
 		};
 	}
 
 	export function to(item: notebooks.IOutputItemDto): types.NotebookCellOutputItem {
-		let value: Uint8Array | any;
-		if (Array.isArray(item.valueBytes)) {
-			value = new Uint8Array(item.valueBytes);
-		} else {
-			value = item.value;
-		}
-		return new types.NotebookCellOutputItem(value, item.mime, item.metadata);
+		return new types.NotebookCellOutputItem(new Uint8Array(item.valueBytes), item.mime, item.metadata);
 	}
 }
 
@@ -1684,18 +1669,15 @@ export namespace NotebookDocumentContentOptions {
 	}
 }
 
-export namespace NotebookKernelPreload {
-	export function from(preload: vscode.NotebookKernelPreload): { uri: UriComponents; provides: string[] } {
+export namespace NotebookRendererScript {
+	export function from(preload: vscode.NotebookRendererScript): { uri: UriComponents; provides: string[] } {
 		return {
 			uri: preload.uri,
-			// todo@connor4312: the conditional here can be removed after a migration period
-			provides: typeof preload.provides === 'string'
-				? [preload.provides]
-				: preload.provides ?? []
+			provides: preload.provides
 		};
 	}
-	export function to(preload: { uri: UriComponents; provides: string[] }): vscode.NotebookKernelPreload {
-		return new types.NotebookKernelPreload(URI.revive(preload.uri), preload.provides);
+	export function to(preload: { uri: UriComponents; provides: string[] }): vscode.NotebookRendererScript {
+		return new types.NotebookRendererScript(URI.revive(preload.uri), preload.provides);
 	}
 }
 
diff --git a/src/vs/workbench/api/common/extHostTypes.ts b/src/vs/workbench/api/common/extHostTypes.ts
index cb45ef3fce5..ece6bab4537 100644
--- a/src/vs/workbench/api/common/extHostTypes.ts
+++ b/src/vs/workbench/api/common/extHostTypes.ts
@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { coalesceInPlace, equals } from 'vs/base/common/arrays';
+import { asArray, coalesceInPlace, equals } from 'vs/base/common/arrays';
 import { illegalArgument } from 'vs/base/common/errors';
 import { IRelativePattern } from 'vs/base/common/glob';
 import { isMarkdownString, MarkdownString as BaseMarkdownString } from 'vs/base/common/htmlContent';
@@ -3112,7 +3112,8 @@ export class NotebookCellOutputItem {
 		if (!obj) {
 			return false;
 		}
-		return typeof (<vscode.NotebookCellOutputItem>obj).mime === 'string';
+		return typeof (<vscode.NotebookCellOutputItem>obj).mime === 'string'
+			&& (<vscode.NotebookCellOutputItem>obj).data instanceof Uint8Array;
 	}
 
 	static error(err: Error | { name: string, message?: string, stack?: string }, metadata?: { [key: string]: any }): NotebookCellOutputItem {
@@ -3148,18 +3149,11 @@ export class NotebookCellOutputItem {
 		return NotebookCellOutputItem.text(rawStr, mime, metadata);
 	}
 
-	/** @deprecated */
-	public value: Uint8Array | unknown; // JSON'able
-
 	constructor(
 		public data: Uint8Array,
 		public mime: string,
 		public metadata?: { [key: string]: any }
 	) {
-		if (!(data instanceof Uint8Array)) {
-			this.value = data;
-		}
-
 		const mimeNormalized = normalizeMimeType(mime, true);
 		if (!mimeNormalized) {
 			throw new Error('INVALID mime type, must not be empty or falsy: ' + mime);
@@ -3251,14 +3245,15 @@ export enum NotebookControllerAffinity {
 	Preferred = 2
 }
 
-export class NotebookKernelPreload {
-	public readonly provides: string[];
+export class NotebookRendererScript {
+
+	public provides: string[];
 
 	constructor(
-		public readonly uri: vscode.Uri,
+		public uri: vscode.Uri,
 		provides: string | string[] = []
 	) {
-		this.provides = typeof provides === 'string' ? [provides] : provides;
+		this.provides = asArray(provides);
 	}
 }
 
diff --git a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
index 45dd563cb91..5114543cfa5 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
+++ b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
@@ -16,7 +16,7 @@ import { IModelService } from 'vs/editor/common/services/modelService';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { ITextModelContentProvider, ITextModelService } from 'vs/editor/common/services/resolverService';
 import * as nls from 'vs/nls';
-import { Extensions, IConfigurationRegistry } from 'vs/platform/configuration/common/configurationRegistry';
+import { Extensions, IConfigurationPropertySchema, IConfigurationRegistry } from 'vs/platform/configuration/common/configurationRegistry';
 import { SyncDescriptor } from 'vs/platform/instantiation/common/descriptors';
 import { registerSingleton } from 'vs/platform/instantiation/common/extensions';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
@@ -30,7 +30,7 @@ import { NotebookEditor } from 'vs/workbench/contrib/notebook/browser/notebookEd
 import { NotebookEditorInput } from 'vs/workbench/contrib/notebook/common/notebookEditorInput';
 import { INotebookService } from 'vs/workbench/contrib/notebook/common/notebookService';
 import { NotebookService } from 'vs/workbench/contrib/notebook/browser/notebookServiceImpl';
-import { CellKind, CellToolbarLocKey, CellToolbarVisibility, CellUri, DisplayOrderKey, UndoRedoPerCell, ExperimentalUseMarkdownRenderer, getCellUndoRedoComparisonKey, IResolvedNotebookEditorModel, NotebookDocumentBackupData, NotebookTextDiffEditorPreview, NotebookWorkingCopyTypeIdentifier, ShowCellStatusBarKey, CompactView, FocusIndicator, InsertToolbarPosition, GlobalToolbar, ConsolidatedOutputButton, ShowFoldingControls, DragAndDropEnabled, ShowCellStatusBarAfterExecuteKey } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { CellKind, CellToolbarLocKey, CellToolbarVisibility, CellUri, DisplayOrderKey, UndoRedoPerCell, ExperimentalUseMarkdownRenderer, getCellUndoRedoComparisonKey, IResolvedNotebookEditorModel, NotebookDocumentBackupData, NotebookTextDiffEditorPreview, NotebookWorkingCopyTypeIdentifier, ShowCellStatusBarKey, CompactView, FocusIndicator, InsertToolbarPosition, GlobalToolbar, ConsolidatedOutputButton, ShowFoldingControls, DragAndDropEnabled, ShowCellStatusBarAfterExecuteKey, NotebookCellEditorOptionsCustomizations } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { IUndoRedoService } from 'vs/platform/undoRedo/common/undoRedo';
 import { INotebookEditorModelResolverService } from 'vs/workbench/contrib/notebook/common/notebookEditorModelResolverService';
@@ -43,7 +43,7 @@ import { NotebookCellStatusBarService } from 'vs/workbench/contrib/notebook/brow
 import { INotebookEditorService } from 'vs/workbench/contrib/notebook/browser/notebookEditorService';
 import { NotebookEditorWidgetService } from 'vs/workbench/contrib/notebook/browser/notebookEditorServiceImpl';
 import { IJSONContributionRegistry, Extensions as JSONExtensions } from 'vs/platform/jsonschemas/common/jsonContributionRegistry';
-import { IJSONSchema } from 'vs/base/common/jsonSchema';
+import { IJSONSchema, IJSONSchemaMap } from 'vs/base/common/jsonSchema';
 import { Event } from 'vs/base/common/event';
 import { getFormatedMetadataJSON } from 'vs/workbench/contrib/notebook/browser/diff/diffElementViewModel';
 import { NotebookModelResolverServiceImpl } from 'vs/workbench/contrib/notebook/common/notebookEditorModelResolverServiceImpl';
@@ -84,6 +84,7 @@ import 'vs/workbench/contrib/notebook/browser/diff/notebookDiffActions';
 
 // Output renderers registration
 import 'vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform';
+import { editorOptionsRegistry } from 'vs/editor/common/config/editorOptions';
 
 /*--------------------------------------------------------------------------------------------- */
 
@@ -548,6 +549,44 @@ registerSingleton(INotebookEditorService, NotebookEditorWidgetService, true);
 registerSingleton(INotebookKernelService, NotebookKernelService, true);
 registerSingleton(INotebookRendererMessagingService, NotebookRendererMessagingService, true);
 
+const schemas: IJSONSchemaMap = {};
+function isConfigurationPropertySchema(x: IConfigurationPropertySchema | { [path: string]: IConfigurationPropertySchema; }): x is IConfigurationPropertySchema {
+	return (typeof x.type !== 'undefined' || typeof x.anyOf !== 'undefined');
+}
+for (const editorOption of editorOptionsRegistry) {
+	const schema = editorOption.schema;
+	if (schema) {
+		if (isConfigurationPropertySchema(schema)) {
+			schemas[`editor.${editorOption.name}`] = schema;
+		} else {
+			for (let key in schema) {
+				if (Object.hasOwnProperty.call(schema, key)) {
+					schemas[key] = schema[key];
+				}
+			}
+		}
+	}
+}
+
+const editorOptionsCustomizationSchema: IConfigurationPropertySchema = {
+	description: nls.localize('notebook.editorOptions.experimentalCustomization', 'Notebook Cell editor options customization.'),
+	default: {},
+	allOf: [
+		{
+			properties: schemas,
+		}
+		// , {
+		// 	patternProperties: {
+		// 		'^\\[.*\\]$': {
+		// 			type: 'object',
+		// 			default: {},
+		// 			properties: schemas
+		// 		}
+		// 	}
+		// }
+	]
+};
+
 const configurationRegistry = Registry.as<IConfigurationRegistry>(Extensions.Configuration);
 configurationRegistry.registerConfiguration({
 	id: 'notebook',
@@ -654,6 +693,7 @@ configurationRegistry.registerConfiguration({
 			type: 'boolean',
 			default: true,
 			tags: ['notebookLayout']
-		}
+		},
+		[NotebookCellEditorOptionsCustomizations]: editorOptionsCustomizationSchema
 	}
 });
diff --git a/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts b/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
index 8025957acc6..377b81e5bd5 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
+++ b/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
@@ -685,6 +685,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 			.monaco-workbench .notebookOverlay .cell-list-top-cell-toolbar-container .monaco-toolbar .action-label, .monaco-workbench .notebookOverlay > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row .cell-bottom-toolbar-container .monaco-toolbar .action-label {
 				padding: 0px !important;
 				justify-content: center;
+				border-radius: 4px;
 			}`);
 
 			styleSheets.push(`
@@ -692,7 +693,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 			.monaco-workbench .notebookOverlay .cell-list-top-cell-toolbar-container, .monaco-workbench .notebookOverlay > .cell-list-container > .monaco-list > .monaco-scrollable-element > .monaco-list-rows > .monaco-list-row .cell-bottom-toolbar-container {
 				align-items: flex-start;
 				justify-content: left;
-				margin: 0 16px 0 8px;
+				margin: 0 16px 0 ${8 + codeCellLeftMargin}px;
 			}`);
 
 			styleSheets.push(`
@@ -1386,7 +1387,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 			// no cached view state so we are rendering the first viewport
 			// after above async call, we already get init height for markdown cells, we can update their offset
 			let offset = 0;
-			const offsetUpdateRequests: { id: string, top: number }[] = [];
+			const offsetUpdateRequests: { id: string, top: number; }[] = [];
 			const scrollBottom = Math.max(this._dimension?.height ?? 0, 1080);
 			for (const cell of viewModel.viewCells) {
 				if (cell.cellKind === CellKind.Markup) {
@@ -1450,7 +1451,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 
 		if (this._list) {
 			state.scrollPosition = { left: this._list.scrollLeft, top: this._list.scrollTop };
-			const cellHeights: { [key: number]: number } = {};
+			const cellHeights: { [key: number]: number; } = {};
 			for (let i = 0; i < this.viewModel!.length; i++) {
 				const elm = this.viewModel!.cellAt(i) as CellViewModel;
 				if (elm.cellKind === CellKind.Code) {
@@ -1476,7 +1477,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 		}
 
 		// Save contribution view states
-		const contributionsState: { [key: string]: unknown } = {};
+		const contributionsState: { [key: string]: unknown; } = {};
 		for (const [id, contribution] of this._contributions) {
 			if (typeof contribution.saveViewState === 'function') {
 				contributionsState[id] = contribution.saveViewState();
@@ -2463,7 +2464,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 
 		this._webview.removeInsets(removedItems);
 
-		const markdownUpdateItems: { id: string, top: number }[] = [];
+		const markdownUpdateItems: { id: string, top: number; }[] = [];
 		for (const cellId of this._webview.markdownPreviewMapping.keys()) {
 			const cell = this.viewModel?.viewCells.find(cell => cell.id === cellId);
 			if (cell) {
@@ -2503,21 +2504,21 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 		}
 	}
 
-	markdownCellDragStart(cellId: string, event: { dragOffsetY: number }): void {
+	markdownCellDragStart(cellId: string, event: { dragOffsetY: number; }): void {
 		const cell = this.getCellById(cellId);
 		if (cell instanceof MarkdownCellViewModel) {
 			this._dndController?.startExplicitDrag(cell, event.dragOffsetY);
 		}
 	}
 
-	markdownCellDrag(cellId: string, event: { dragOffsetY: number }): void {
+	markdownCellDrag(cellId: string, event: { dragOffsetY: number; }): void {
 		const cell = this.getCellById(cellId);
 		if (cell instanceof MarkdownCellViewModel) {
 			this._dndController?.explicitDrag(cell, event.dragOffsetY);
 		}
 	}
 
-	markdownCellDrop(cellId: string, event: { dragOffsetY: number, ctrlKey: boolean, altKey: boolean }): void {
+	markdownCellDrop(cellId: string, event: { dragOffsetY: number, ctrlKey: boolean, altKey: boolean; }): void {
 		const cell = this.getCellById(cellId);
 		if (cell instanceof MarkdownCellViewModel) {
 			this._dndController?.explicitDrop(cell, event);
@@ -2573,7 +2574,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 		super.dispose();
 	}
 
-	toJSON(): { notebookUri: URI | undefined } {
+	toJSON(): { notebookUri: URI | undefined; } {
 		return {
 			notebookUri: this.viewModel?.uri,
 		};
diff --git a/src/vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform.ts b/src/vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform.ts
index 60c40a9e613..589f638644c 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform.ts
@@ -6,7 +6,6 @@
 import * as DOM from 'vs/base/browser/dom';
 import { Disposable, DisposableStore, toDisposable } from 'vs/base/common/lifecycle';
 import { dirname } from 'vs/base/common/resources';
-import { isArray } from 'vs/base/common/types';
 import { URI } from 'vs/base/common/uri';
 import { MarkdownRenderer } from 'vs/editor/browser/core/markdownRenderer';
 import { IEditorConstructionOptions } from 'vs/editor/browser/editorBrowser';
@@ -109,14 +108,7 @@ class JSONRendererContrib extends CodeRendererContrib {
 	}
 
 	override render(output: ICellOutputViewModel, items: IOutputItemDto[], container: HTMLElement): IRenderOutput {
-		const str = items.map(item => {
-			if (isArray(item.valueBytes)) {
-				return getStringValue(item);
-			} else {
-				return JSON.stringify(item.value, null, '\t');
-			}
-		}).join('');
-
+		const str = items.map(getStringValue).join('');
 		return this._render(output, container, str, 'jsonc');
 	}
 }
@@ -170,57 +162,6 @@ class StderrRendererContrib extends StreamRendererContrib {
 	}
 }
 
-/** @deprecated */
-class ErrorRendererContrib extends Disposable implements IOutputRendererContribution {
-	getType() {
-		return RenderOutputType.Mainframe;
-	}
-
-	getMimetypes() {
-		return ['application/x.notebook.error-traceback'];
-	}
-
-	constructor(
-		public notebookEditor: ICommonNotebookEditor,
-		@IThemeService private readonly themeService: IThemeService,
-		@IInstantiationService private readonly instantiationService: IInstantiationService,
-
-	) {
-		super();
-	}
-
-	render(output: ICellOutputViewModel, items: IOutputItemDto[], container: HTMLElement, notebookUri: URI): IRenderOutput {
-		const linkDetector = this.instantiationService.createInstance(LinkDetector);
-		items.forEach(item => {
-			const data: any = item.value;
-			const header = document.createElement('div');
-			const headerMessage = data.ename && data.evalue
-				? `${data.ename}: ${data.evalue}`
-				: data.ename || data.evalue;
-			if (headerMessage) {
-				header.innerText = headerMessage;
-				container.appendChild(header);
-			}
-			const traceback = document.createElement('pre');
-			traceback.classList.add('traceback');
-			if (data.traceback) {
-				for (let j = 0; j < data.traceback.length; j++) {
-					traceback.appendChild(handleANSIOutput(data.traceback[j], linkDetector, this.themeService, undefined));
-				}
-			}
-			container.appendChild(traceback);
-			container.classList.add('error');
-			return { type: RenderOutputType.Mainframe };
-
-		});
-
-		return { type: RenderOutputType.Mainframe };
-	}
-
-	_render() {
-	}
-}
-
 class JSErrorRendererContrib implements IOutputRendererContribution {
 
 	constructor(
@@ -381,17 +322,10 @@ class ImgRendererContrib extends Disposable implements IOutputRendererContributi
 
 		for (let item of items) {
 
-			let src: string;
-			if (Array.isArray(item.valueBytes)) {
-				const bytes = new Uint8Array(item.valueBytes);
-				const blob = new Blob([bytes], { type: item.mime });
-				src = URL.createObjectURL(blob);
-				disposable.add(toDisposable(() => URL.revokeObjectURL(src)));
-			} else {
-				// OLD
-				const imagedata = item.value;
-				src = `data:${item.mime};base64,${imagedata}`;
-			}
+			const bytes = new Uint8Array(item.valueBytes);
+			const blob = new Blob([bytes], { type: item.mime });
+			const src = URL.createObjectURL(blob);
+			disposable.add(toDisposable(() => URL.revokeObjectURL(src)));
 
 			const image = document.createElement('img');
 			image.src = src;
@@ -414,17 +348,11 @@ OutputRendererRegistry.registerOutputTransform(CodeRendererContrib);
 OutputRendererRegistry.registerOutputTransform(JSErrorRendererContrib);
 OutputRendererRegistry.registerOutputTransform(StreamRendererContrib);
 OutputRendererRegistry.registerOutputTransform(StderrRendererContrib);
-OutputRendererRegistry.registerOutputTransform(ErrorRendererContrib);
 
 // --- utils ---
 function getStringValue(item: IOutputItemDto): string {
-	if (Array.isArray(item.valueBytes)) {
-		// todo@jrieken NOT proper, should be VSBuffer
-		return new TextDecoder().decode(new Uint8Array(item.valueBytes));
-	} else {
-		// "old" world
-		return Array.isArray(item.value) ? item.value.join('') : String(item.value);
-	}
+	// todo@jrieken NOT proper, should be VSBuffer
+	return new TextDecoder().decode(new Uint8Array(item.valueBytes));
 }
 
 function getOutputSimpleEditorOptions(): IEditorConstructionOptions {
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
index 6c31eb26680..febd9112487 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts
@@ -192,7 +192,7 @@ export interface ICreationRequestMessage {
 	type: 'html';
 	content:
 	| { type: RenderOutputType.Html; htmlContent: string }
-	| { type: RenderOutputType.Extension; outputId: string; value: unknown; valueBytes: Uint8Array, metadata: unknown; mimeType: string };
+	| { type: RenderOutputType.Extension; outputId: string; valueBytes: Uint8Array, metadata: unknown; mimeType: string };
 	cellId: string;
 	outputId: string;
 	cellTop: number;
@@ -1513,7 +1513,6 @@ var requirejs = (function() {
 					type: RenderOutputType.Extension,
 					outputId: output.outputId,
 					mimeType: content.mimeType,
-					value: outputDto?.value,
 					valueBytes: new Uint8Array(outputDto?.valueBytes ?? []),
 					metadata: outputDto?.metadata,
 				},
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/cellEditorOptions.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/cellEditorOptions.ts
index bf7dc140594..8b38e913b72 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/cellEditorOptions.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/cellEditorOptions.ts
@@ -47,41 +47,50 @@ export class CellEditorOptions extends Disposable {
 	private readonly _onDidChange = new Emitter<IEditorOptions>();
 	readonly onDidChange: Event<IEditorOptions> = this._onDidChange.event;
 
-	constructor(readonly notebookOptions: NotebookOptions, readonly configurationService: IConfigurationService, language: string) {
+	constructor(readonly notebookOptions: NotebookOptions, readonly configurationService: IConfigurationService, readonly language: string) {
 		super();
 		this._register(configurationService.onDidChangeConfiguration(e => {
 			if (e.affectsConfiguration('editor') || e.affectsConfiguration('notebook')) {
-				this._value = computeEditorOptions();
+				this._value = this._computeEditorOptions();
 				this._onDidChange.fire(this.value);
 			}
 		}));
 
 		this._register(notebookOptions.onDidChangeOptions(e => {
-			if (e.cellStatusBarVisibility || e.editorTopPadding) {
-				this._value = computeEditorOptions();
+			if (e.cellStatusBarVisibility || e.editorTopPadding || e.editorOptionsCustomizations) {
+				this._value = this._computeEditorOptions();
 				this._onDidChange.fire(this.value);
 			}
 		}));
 
-		const computeEditorOptions = () => {
-			const editorPadding = this.notebookOptions.computeEditorPadding();
-			const renderLiNumbers = configurationService.getValue<'on' | 'off'>('notebook.lineNumbers') === 'on';
-			const lineNumbers: LineNumbersType = renderLiNumbers ? 'on' : 'off';
-			const editorOptions = deepClone(configurationService.getValue<IEditorOptions>('editor', { overrideIdentifier: language }));
-			const computed = {
-				...editorOptions,
-				...CellEditorOptions.fixedEditorOptions,
-				...{ padding: editorPadding, lineNumbers },
-			};
+		this._value = this._computeEditorOptions();
+	}
 
-			if (!computed.folding) {
-				computed.lineDecorationsWidth = 16;
+	private _computeEditorOptions() {
+		const editorPadding = this.notebookOptions.computeEditorPadding();
+		const renderLiNumbers = this.configurationService.getValue<'on' | 'off'>('notebook.lineNumbers') === 'on';
+		const lineNumbers: LineNumbersType = renderLiNumbers ? 'on' : 'off';
+		const editorOptions = deepClone(this.configurationService.getValue<IEditorOptions>('editor', { overrideIdentifier: this.language }));
+		const editorOptionsOverrideRaw = this.notebookOptions.getLayoutConfiguration().editorOptionsCustomizations ?? {};
+		let editorOptionsOverride: { [key: string]: any } = {};
+		for (let key in editorOptionsOverrideRaw) {
+			if (key.indexOf('editor.') === 0) {
+				editorOptionsOverride[key.substr(7)] = editorOptionsOverrideRaw[key];
 			}
-
-			return computed;
+		}
+		const computed = {
+			...editorOptions,
+			...CellEditorOptions.fixedEditorOptions,
+			... { lineNumbers },
+			...editorOptionsOverride,
+			...{ padding: editorPadding }
 		};
 
-		this._value = computeEditorOptions();
+		if (!computed.folding) {
+			computed.lineDecorationsWidth = 16;
+		}
+
+		return computed;
 	}
 
 	override dispose(): void {
diff --git a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
index ff86aa25c5f..d3ce5beb2cd 100644
--- a/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
+++ b/src/vs/workbench/contrib/notebook/browser/view/renderers/webviewPreloads.ts
@@ -463,7 +463,6 @@ async function webviewPreloads(style: PreloadStyles, options: PreloadOptions, re
 		outputId?: string;
 
 		mime: string;
-		value: unknown;
 		metadata: unknown;
 
 		text(): string;
@@ -643,15 +642,13 @@ async function webviewPreloads(style: PreloadStyles, options: PreloadOptions, re
 							rendererApi.renderCell(outputId, {
 								element: outputNode,
 								mime: content.mimeType,
-								value: content.value,
 								metadata: content.metadata,
 								data() {
 									return content.valueBytes;
 								},
 								bytes() { return this.data(); },
 								text() {
-									return new TextDecoder().decode(content.valueBytes)
-										|| String(content.value); //todo@jrieken remove this once `value` is gone!
+									return new TextDecoder().decode(content.valueBytes);
 								},
 								json() {
 									return JSON.parse(this.text());
@@ -1037,7 +1034,6 @@ async function webviewPreloads(style: PreloadStyles, options: PreloadOptions, re
 
 			markdownRenderers[0].api?.renderCell(id, {
 				element,
-				value: content,
 				mime: 'text/markdown',
 				metadata: undefined,
 				outputId: undefined,
diff --git a/src/vs/workbench/contrib/notebook/common/notebookCommon.ts b/src/vs/workbench/contrib/notebook/common/notebookCommon.ts
index de639c6c2a9..96973ca5a9a 100644
--- a/src/vs/workbench/contrib/notebook/common/notebookCommon.ts
+++ b/src/vs/workbench/contrib/notebook/common/notebookCommon.ts
@@ -173,8 +173,7 @@ export interface IOrderedMimeType {
 
 export interface IOutputItemDto {
 	readonly mime: string;
-	readonly value: unknown;
-	readonly valueBytes?: number[];
+	readonly valueBytes: number[];
 	readonly metadata?: Record<string, unknown>;
 }
 
@@ -603,7 +602,6 @@ const _mimeTypeInfo = new Map<string, MimeTypeInfo>([
 	['application/x.notebook.stdout', { alwaysSecure: true, supportedByCore: true, mergeable: true }],
 	['application/x.notebook.stderr', { alwaysSecure: true, supportedByCore: true, mergeable: true }],
 	['application/x.notebook.stream', { alwaysSecure: true, supportedByCore: true, mergeable: true }], // deprecated
-	['application/x.notebook.error-traceback', { alwaysSecure: true, supportedByCore: true }], // deprecated
 ]);
 
 export function mimeTypeIsAlwaysSecure(mimeType: string): boolean {
@@ -922,6 +920,7 @@ export const UndoRedoPerCell = 'notebook.undoRedoPerCell';
 export const ConsolidatedOutputButton = 'notebook.consolidatedOutputButton';
 export const ShowFoldingControls = 'notebook.showFoldingControls';
 export const DragAndDropEnabled = 'notebook.dragAndDropEnabled';
+export const NotebookCellEditorOptionsCustomizations = 'notebook.editorOptionsCustomizations';
 
 export const enum CellStatusbarAlignment {
 	Left = 1,
diff --git a/src/vs/workbench/contrib/notebook/common/notebookOptions.ts b/src/vs/workbench/contrib/notebook/common/notebookOptions.ts
index be3c9320288..58f43fec488 100644
--- a/src/vs/workbench/contrib/notebook/common/notebookOptions.ts
+++ b/src/vs/workbench/contrib/notebook/common/notebookOptions.ts
@@ -6,7 +6,7 @@
 import { Emitter } from 'vs/base/common/event';
 import { IDisposable } from 'vs/base/common/lifecycle';
 import { IConfigurationChangeEvent, IConfigurationService } from 'vs/platform/configuration/common/configuration';
-import { CellToolbarLocKey, CellToolbarVisibility, CompactView, ConsolidatedOutputButton, DragAndDropEnabled, ExperimentalInsertToolbarAlignment, FocusIndicator, GlobalToolbar, InsertToolbarPosition, ShowCellStatusBarAfterExecuteKey, ShowCellStatusBarKey, ShowFoldingControls } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { CellToolbarLocKey, CellToolbarVisibility, CompactView, ConsolidatedOutputButton, DragAndDropEnabled, ExperimentalInsertToolbarAlignment, FocusIndicator, GlobalToolbar, InsertToolbarPosition, NotebookCellEditorOptionsCustomizations, ShowCellStatusBarAfterExecuteKey, ShowCellStatusBarKey, ShowFoldingControls } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 
 const SCROLLABLE_ELEMENT_PADDING_TOP = 18;
 
@@ -58,6 +58,7 @@ export interface NotebookLayoutConfiguration {
 	dragAndDropEnabled: boolean;
 	fontSize: number;
 	focusIndicatorLeftMargin: number;
+	editorOptionsCustomizations: any | undefined;
 }
 
 interface NotebookOptionsChangeEvent {
@@ -75,6 +76,7 @@ interface NotebookOptionsChangeEvent {
 	consolidatedOutputButton?: boolean;
 	dragAndDropEnabled?: boolean;
 	fontSize?: boolean;
+	editorOptionsCustomizations?: boolean;
 }
 
 const defaultConfigConstants = {
@@ -118,6 +120,7 @@ export class NotebookOptions {
 		const showFoldingControls = this._computeShowFoldingControlsOption();
 		// const { bottomToolbarGap, bottomToolbarHeight } = this._computeBottomToolbarDimensions(compactView, insertToolbarPosition, insertToolbarAlignment);
 		const fontSize = this.configurationService.getValue<number>('editor.fontSize');
+		const editorOptionsCustomizations = this.configurationService.getValue(NotebookCellEditorOptionsCustomizations);
 
 		this._disposables = [];
 		this._layoutConfiguration = {
@@ -147,7 +150,8 @@ export class NotebookOptions {
 			insertToolbarPosition,
 			insertToolbarAlignment,
 			showFoldingControls,
-			fontSize
+			fontSize,
+			editorOptionsCustomizations
 		};
 
 		this._disposables.push(this.configurationService.onDidChangeConfiguration(e => {
@@ -176,6 +180,7 @@ export class NotebookOptions {
 		const showFoldingControls = e.affectsConfiguration(ShowFoldingControls);
 		const dragAndDropEnabled = e.affectsConfiguration(DragAndDropEnabled);
 		const fontSize = e.affectsConfiguration('editor.fontSize');
+		const editorOptionsCustomizations = e.affectsConfiguration(NotebookCellEditorOptionsCustomizations);
 
 		if (
 			!cellStatusBarVisibility
@@ -190,7 +195,8 @@ export class NotebookOptions {
 			&& !consolidatedOutputButton
 			&& !showFoldingControls
 			&& !dragAndDropEnabled
-			&& !fontSize) {
+			&& !fontSize
+			&& !editorOptionsCustomizations) {
 			return;
 		}
 
@@ -252,6 +258,10 @@ export class NotebookOptions {
 			configuration.fontSize = this.configurationService.getValue<number>('editor.fontSize');
 		}
 
+		if (editorOptionsCustomizations) {
+			configuration.editorOptionsCustomizations = this.configurationService.getValue(NotebookCellEditorOptionsCustomizations);
+		}
+
 		this._layoutConfiguration = Object.freeze(configuration);
 
 		// trigger event
@@ -268,7 +278,8 @@ export class NotebookOptions {
 			showFoldingControls,
 			consolidatedOutputButton,
 			dragAndDropEnabled,
-			fontSize: fontSize
+			fontSize,
+			editorOptionsCustomizations
 		});
 	}
 
diff --git a/src/vs/workbench/contrib/notebook/test/notebookDiff.test.ts b/src/vs/workbench/contrib/notebook/test/notebookDiff.test.ts
index 724ff468ed0..3e612b388c9 100644
--- a/src/vs/workbench/contrib/notebook/test/notebookDiff.test.ts
+++ b/src/vs/workbench/contrib/notebook/test/notebookDiff.test.ts
@@ -14,9 +14,9 @@ suite('NotebookCommon', () => {
 
 	test('diff different source', async () => {
 		await withTestNotebookDiffModel([
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
 		], [
-			['y', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
+			['y', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
 		], (model, accessor) => {
 			const diff = new LcsDiff(new CellSequence(model.original.notebook), new CellSequence(model.modified.notebook));
 			const diffResult = diff.ComputeDiff(false);
@@ -44,10 +44,10 @@ suite('NotebookCommon', () => {
 
 	test('diff different output', async () => {
 		await withTestNotebookDiffModel([
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '5' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [5] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
 			['', 'javascript', CellKind.Code, [], {}]
 		], [
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someOtherId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 3 }],
 			['', 'javascript', CellKind.Code, [], {}]
 		], (model, accessor) => {
 			const diff = new LcsDiff(new CellSequence(model.original.notebook), new CellSequence(model.modified.notebook));
@@ -145,12 +145,12 @@ suite('NotebookCommon', () => {
 
 	test('diff foo/foe', async () => {
 		await withTestNotebookDiffModel([
-			[['def foe(x, y):\n', '    return x + y\n', 'foe(3, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '6' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
-			[['def foo(x, y):\n', '    return x * y\n', 'foo(1, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '2' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 6 }],
+			[['def foe(x, y):\n', '    return x + y\n', 'foe(3, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [6] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
+			[['def foo(x, y):\n', '    return x * y\n', 'foo(1, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [2] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 6 }],
 			['', 'javascript', CellKind.Code, [], {}]
 		], [
-			[['def foo(x, y):\n', '    return x * y\n', 'foo(1, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '6' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
-			[['def foe(x, y):\n', '    return x + y\n', 'foe(3, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '2' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 6 }],
+			[['def foo(x, y):\n', '    return x * y\n', 'foo(1, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [6] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 5 }],
+			[['def foe(x, y):\n', '    return x + y\n', 'foe(3, 2)'].join(''), 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [2] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 6 }],
 			['', 'javascript', CellKind.Code, [], {}]
 		], (model, accessor) => {
 			const diff = new LcsDiff(new CellSequence(model.original.notebook), new CellSequence(model.modified.notebook));
@@ -272,13 +272,13 @@ suite('NotebookCommon', () => {
 		await withTestNotebookDiffModel([
 			['# Description', 'markdown', CellKind.Markup, [], { custom: { metadata: {} } }],
 			['x = 3', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: true } }, executionOrder: 1 }],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
 			['x', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: false } } }]
 		], [
 			['# Description', 'markdown', CellKind.Markup, [], { custom: { metadata: {} } }],
 			['x = 3', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: true } }, executionOrder: 1 }],
 			['x', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: false } } }],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }]
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }]
 		], async (model) => {
 			const diff = new LcsDiff(new CellSequence(model.original.notebook), new CellSequence(model.modified.notebook));
 			const diffResult = diff.ComputeDiff(false);
@@ -305,18 +305,18 @@ suite('NotebookCommon', () => {
 		await withTestNotebookDiffModel([
 			['# Description', 'markdown', CellKind.Markup, [], { custom: { metadata: {} } }],
 			['x = 3', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: true } }, executionOrder: 1 }],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
 			['x', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: false } } }],
 			['x = 5', 'javascript', CellKind.Code, [], {}],
 			['x', 'javascript', CellKind.Code, [], {}],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '5' }] }], {}],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [5] }] }], {}],
 		], [
 			['# Description', 'markdown', CellKind.Markup, [], { custom: { metadata: {} } }],
 			['x = 3', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: true } }, executionOrder: 1 }],
 			['x', 'javascript', CellKind.Code, [], { custom: { metadata: { collapsed: false } } }],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '3' }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [3] }] }], { custom: { metadata: { collapsed: false } }, executionOrder: 1 }],
 			['x = 5', 'javascript', CellKind.Code, [], {}],
-			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', value: '5' }] }], {}],
+			['x', 'javascript', CellKind.Code, [{ outputId: 'someId', outputs: [{ mime: 'text/plain', valueBytes: [5] }] }], {}],
 			['x', 'javascript', CellKind.Code, [], {}],
 		], async (model) => {
 			const diff = new LcsDiff(new CellSequence(model.original.notebook), new CellSequence(model.modified.notebook));
diff --git a/src/vs/workbench/contrib/notebook/test/notebookTextModel.test.ts b/src/vs/workbench/contrib/notebook/test/notebookTextModel.test.ts
index 59bb65360de..3e799efe395 100644
--- a/src/vs/workbench/contrib/notebook/test/notebookTextModel.test.ts
+++ b/src/vs/workbench/contrib/notebook/test/notebookTextModel.test.ts
@@ -10,6 +10,11 @@ import { IUndoRedoService } from 'vs/platform/undoRedo/common/undoRedo';
 import { IModeService } from 'vs/editor/common/services/modeService';
 
 suite('NotebookTextModel', () => {
+
+	function valueBytesFromString(value: string) {
+		return Array.from(new TextEncoder().encode(value));
+	}
+
 	const instantiationService = setupInstantiationService();
 	const modeService = instantiationService.get(IModeService);
 	instantiationService.spy(IUndoRedoService, 'pushElement');
@@ -184,7 +189,7 @@ suite('NotebookTextModel', () => {
 					editType: CellEditType.Output,
 					outputs: [{
 						outputId: 'someId',
-						outputs: [{ mime: 'text/markdown', value: '_Hello_' }]
+						outputs: [{ mime: 'text/markdown', valueBytes: valueBytesFromString('_Hello_') }]
 					}]
 				}], true, undefined, () => undefined, undefined);
 
@@ -198,7 +203,7 @@ suite('NotebookTextModel', () => {
 					append: true,
 					outputs: [{
 						outputId: 'someId2',
-						outputs: [{ mime: 'text/markdown', value: '_Hello2_' }]
+						outputs: [{ mime: 'text/markdown', valueBytes: valueBytesFromString('_Hello2_') }]
 					}]
 				}], true, undefined, () => undefined, undefined);
 
@@ -214,7 +219,7 @@ suite('NotebookTextModel', () => {
 					editType: CellEditType.Output,
 					outputs: [{
 						outputId: 'someId3',
-						outputs: [{ mime: 'text/plain', value: 'Last, replaced output' }]
+						outputs: [{ mime: 'text/plain', valueBytes: valueBytesFromString('Last, replaced output') }]
 					}]
 				}], true, undefined, () => undefined, undefined);
 
@@ -242,7 +247,7 @@ suite('NotebookTextModel', () => {
 						append: true,
 						outputs: [{
 							outputId: 'append1',
-							outputs: [{ mime: 'text/markdown', value: 'append 1' }]
+							outputs: [{ mime: 'text/markdown', valueBytes: valueBytesFromString('append 1') }]
 						}]
 					},
 					{
@@ -251,7 +256,7 @@ suite('NotebookTextModel', () => {
 						append: true,
 						outputs: [{
 							outputId: 'append2',
-							outputs: [{ mime: 'text/markdown', value: 'append 2' }]
+							outputs: [{ mime: 'text/markdown', valueBytes: valueBytesFromString('append 2') }]
 						}]
 					}
 				], true, undefined, () => undefined, undefined);
@@ -418,7 +423,7 @@ suite('NotebookTextModel', () => {
 			const success1 = model.applyEdits(
 				[{
 					editType: CellEditType.Output, index: 0, outputs: [
-						{ outputId: 'out1', outputs: [{ mime: 'application/x.notebook.stream', value: 1 }] }
+						{ outputId: 'out1', outputs: [{ mime: 'application/x.notebook.stream', valueBytes: [1] }] }
 					],
 					append: false
 				}], true, undefined, () => undefined, undefined, false
@@ -430,7 +435,7 @@ suite('NotebookTextModel', () => {
 			const success2 = model.applyEdits(
 				[{
 					editType: CellEditType.Output, index: 0, outputs: [
-						{ outputId: 'out2', outputs: [{ mime: 'application/x.notebook.stream', value: 1 }] }
+						{ outputId: 'out2', outputs: [{ mime: 'application/x.notebook.stream', valueBytes: [1] }] }
 					],
 					append: true
 				}], true, undefined, () => undefined, undefined, false
@@ -457,7 +462,7 @@ suite('NotebookTextModel', () => {
 				const success = model.applyEdits(
 					[{
 						editType: CellEditType.Output, index: 0, outputs: [
-							{ outputId: 'out1', outputs: [{ mime: 'application/x.notebook.stream', value: 1 }] }
+							{ outputId: 'out1', outputs: [{ mime: 'application/x.notebook.stream', valueBytes: [1] }] }
 						],
 						append: false
 					}], true, undefined, () => undefined, undefined, false
@@ -563,14 +568,14 @@ suite('NotebookTextModel', () => {
 
 	test('Destructive sorting in _doApplyEdits #121994', async function () {
 		await withTestNotebook([
-			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}]
+			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}]
 		], async (editor) => {
 
 			const notebook = editor.viewModel.notebookDocument;
 
 			assert.strictEqual(notebook.cells[0].outputs.length, 1);
 			assert.strictEqual(notebook.cells[0].outputs[0].outputs.length, 1);
-			assert.strictEqual(notebook.cells[0].outputs[0].outputs[0].value, 'test');
+			assert.deepStrictEqual(notebook.cells[0].outputs[0].outputs[0].valueBytes, valueBytesFromString('test'));
 
 			const edits: ICellEditOperation[] = [
 				{
@@ -579,7 +584,7 @@ suite('NotebookTextModel', () => {
 				{
 					editType: CellEditType.Output, handle: 0, append: true, outputs: [{
 						outputId: 'newOutput',
-						outputs: [{ mime: 'text/plain', value: 'cba' }, { mime: 'application/foo', value: 'cba' }]
+						outputs: [{ mime: 'text/plain', valueBytes: valueBytesFromString('cba') }, { mime: 'application/foo', valueBytes: valueBytesFromString('cba') }]
 					}]
 				}
 			];
@@ -593,9 +598,9 @@ suite('NotebookTextModel', () => {
 
 	test('Destructive sorting in _doApplyEdits #121994. cell splice between output changes', async function () {
 		await withTestNotebook([
-			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}],
-			['var b = 2;', 'javascript', CellKind.Code, [{ outputId: 'i43', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}],
-			['var c = 3;', 'javascript', CellKind.Code, [{ outputId: 'i44', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}]
+			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}],
+			['var b = 2;', 'javascript', CellKind.Code, [{ outputId: 'i43', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}],
+			['var c = 3;', 'javascript', CellKind.Code, [{ outputId: 'i44', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}]
 		], async (editor) => {
 			const notebook = editor.viewModel.notebookDocument;
 
@@ -609,7 +614,7 @@ suite('NotebookTextModel', () => {
 				{
 					editType: CellEditType.Output, index: 2, append: true, outputs: [{
 						outputId: 'newOutput',
-						outputs: [{ mime: 'text/plain', value: 'cba' }, { mime: 'application/foo', value: 'cba' }]
+						outputs: [{ mime: 'text/plain', valueBytes: valueBytesFromString('cba') }, { mime: 'application/foo', valueBytes: valueBytesFromString('cba') }]
 					}]
 				}
 			];
@@ -626,9 +631,9 @@ suite('NotebookTextModel', () => {
 
 	test('Destructive sorting in _doApplyEdits #121994. cell splice between output changes 2', async function () {
 		await withTestNotebook([
-			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}],
-			['var b = 2;', 'javascript', CellKind.Code, [{ outputId: 'i43', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}],
-			['var c = 3;', 'javascript', CellKind.Code, [{ outputId: 'i44', outputs: [{ mime: 'm/ime', value: 'test' }] }], {}]
+			['var a = 1;', 'javascript', CellKind.Code, [{ outputId: 'i42', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}],
+			['var b = 2;', 'javascript', CellKind.Code, [{ outputId: 'i43', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}],
+			['var c = 3;', 'javascript', CellKind.Code, [{ outputId: 'i44', outputs: [{ mime: 'm/ime', valueBytes: valueBytesFromString('test') }] }], {}]
 		], async (editor) => {
 			const notebook = editor.viewModel.notebookDocument;
 
@@ -636,7 +641,7 @@ suite('NotebookTextModel', () => {
 				{
 					editType: CellEditType.Output, index: 1, append: true, outputs: [{
 						outputId: 'newOutput',
-						outputs: [{ mime: 'text/plain', value: 'cba' }, { mime: 'application/foo', value: 'cba' }]
+						outputs: [{ mime: 'text/plain', valueBytes: valueBytesFromString('cba') }, { mime: 'application/foo', valueBytes: valueBytesFromString('cba') }]
 					}]
 				},
 				{
@@ -645,7 +650,7 @@ suite('NotebookTextModel', () => {
 				{
 					editType: CellEditType.Output, index: 1, append: true, outputs: [{
 						outputId: 'newOutput2',
-						outputs: [{ mime: 'text/plain', value: 'cba' }, { mime: 'application/foo', value: 'cba' }]
+						outputs: [{ mime: 'text/plain', valueBytes: valueBytesFromString('cba') }, { mime: 'application/foo', valueBytes: valueBytesFromString('cba') }]
 					}]
 				}
 			];
diff --git a/src/vs/workbench/test/browser/api/extHostNotebookKernel2.test.ts b/src/vs/workbench/test/browser/api/extHostNotebookKernel2.test.ts
index 5bfdd1356c3..742118b48d0 100644
--- a/src/vs/workbench/test/browser/api/extHostNotebookKernel2.test.ts
+++ b/src/vs/workbench/test/browser/api/extHostNotebookKernel2.test.ts
@@ -165,28 +165,28 @@ suite('NotebookKernel', function () {
 		assert.strictEqual(first.label, 'Far');
 	});
 
-	test('execute - simple createNotebookCellExecutionTask', function () {
+	test('execute - simple createNotebookCellExecution', function () {
 		const kernel = extHostNotebookKernels.createNotebookController(nullExtensionDescription, 'foo', '*', 'Foo');
 
 		extHostNotebookKernels.$acceptNotebookAssociation(0, notebook.uri, true);
 
 		const cell1 = notebook.apiNotebook.cellAt(0);
-		const task = kernel.createNotebookCellExecutionTask(cell1);
+		const task = kernel.createNotebookCellExecution(cell1);
 		task.start();
 		task.end();
 	});
 
-	test('createNotebookCellExecutionTask, must be selected/associated', function () {
+	test('createNotebookCellExecution, must be selected/associated', function () {
 		const kernel = extHostNotebookKernels.createNotebookController(nullExtensionDescription, 'foo', '*', 'Foo');
 		assert.throws(() => {
-			kernel.createNotebookCellExecutionTask(notebook.apiNotebook.cellAt(0));
+			kernel.createNotebookCellExecution(notebook.apiNotebook.cellAt(0));
 		});
 
 		extHostNotebookKernels.$acceptNotebookAssociation(0, notebook.uri, true);
-		kernel.createNotebookCellExecutionTask(notebook.apiNotebook.cellAt(0));
+		kernel.createNotebookCellExecution(notebook.apiNotebook.cellAt(0));
 	});
 
-	test('createNotebookCellExecutionTask, cell must be alive', function () {
+	test('createNotebookCellExecution, cell must be alive', function () {
 		const kernel = extHostNotebookKernels.createNotebookController(nullExtensionDescription, 'foo', '*', 'Foo');
 
 		const cell1 = notebook.apiNotebook.cellAt(0);
@@ -203,7 +203,7 @@ suite('NotebookKernel', function () {
 		assert.strictEqual(cell1.index, -1);
 
 		assert.throws(() => {
-			kernel.createNotebookCellExecutionTask(cell1);
+			kernel.createNotebookCellExecution(cell1);
 		});
 	});
 
@@ -218,15 +218,15 @@ suite('NotebookKernel', function () {
 
 		const cell1 = notebook.apiNotebook.cellAt(0);
 
-		const task = kernel.createNotebookCellExecutionTask(cell1);
+		const task = kernel.createNotebookCellExecution(cell1);
 		task.token.onCancellationRequested(() => tokenCancelCount += 1);
 
 		await extHostNotebookKernels.$cancelCells(0, notebook.uri, [0]);
 		assert.strictEqual(interruptCallCount, 1);
-		assert.strictEqual(tokenCancelCount, 1);
+		assert.strictEqual(tokenCancelCount, 0);
 
 		await extHostNotebookKernels.$cancelCells(0, notebook.uri, [0]);
 		assert.strictEqual(interruptCallCount, 2);
-		assert.strictEqual(tokenCancelCount, 1);
+		assert.strictEqual(tokenCancelCount, 0);
 	});
 });
diff --git a/src/vs/workbench/test/browser/api/extHostTypeConverter.test.ts b/src/vs/workbench/test/browser/api/extHostTypeConverter.test.ts
index 324cdd3c071..9b9e68a2778 100644
--- a/src/vs/workbench/test/browser/api/extHostTypeConverter.test.ts
+++ b/src/vs/workbench/test/browser/api/extHostTypeConverter.test.ts
@@ -91,14 +91,12 @@ suite('ExtHostTypeConverter', function () {
 
 		assert.strictEqual(dto.mime, 'foo/bar');
 		assert.strictEqual(dto.metadata, undefined);
-		assert.strictEqual(dto.value, undefined);
 		assert.deepStrictEqual(dto.valueBytes, Array.from(new TextEncoder().encode('Hello')));
 
 		const item2 = NotebookCellOutputItem.to(dto);
 
 		assert.strictEqual(item2.mime, item.mime);
 		assert.strictEqual(item2.metadata, item.metadata);
-		assert.strictEqual(item2.value, item.value);
 		assert.deepStrictEqual(item2.data, item.data);
 	});
 });