core/homeassistant/components/cast/strings.json

{
  "config": {
    "step": {
      "confirm": {
        "description": "Do you want to set up Google Cast?"
      }
    },
    "abort": {
      "single_instance_allowed": "Only a single configuration of Google Cast is necessary.",
      "no_devices_found": "No Google Cast devices found on the network."
    }
  }
}