core/homeassistant/components/iperf3/strings.json

{
  "services": {
    "speedtest": {
      "description": "Immediately executes a speed test with iperf3.",
      "fields": {
        "host": {
          "description": "The host name of the iperf3 server (already configured) to run a test with.",
          "name": "[%key:common::config_flow::data::host%]"
        }
      },
      "name": "Speedtest"
    }
  }
}