core/homeassistant/components/cast/translations/ja.json

{
    "config": {
        "step": {
            "confirm": {
                "description": "Google Cast\u3092\u30bb\u30c3\u30c8\u30a2\u30c3\u30d7\u3057\u307e\u3059\u304b\uff1f"
            }
        }
    }
}