ha-core/homeassistant/components/update/strings.json

{
  "title": "Update",
  "device_automation": {
    "trigger_type": {
      "changed_states": "{entity_name} update availability changed",
      "turned_on": "{entity_name} got an update available",
      "turned_off": "{entity_name} became up-to-date"
    }
  }
}