Get YouTube Subtitle Metadata

{
  "data": {
    "videoId": "icxrUIGoEg8",
    "channelId": "UCuAXFkgsw1L7xaCfnd5JJOw",
    "availableSubtitles": [
      {
        "vssId": "a.en",
        "lang": "English (Auto-generated)",
        "langCode": "en"
      },
      {
        "vssId": ".en",
        "lang": "English",
        "langCode": "en"
      },
      {
        "vssId": ".zh-Hant",
        "lang": "Chinese (Traditional)",
        "langCode": "zh-Hant"
      }
    ]
  },
  "creditsUsed": 1,
  "creditsAvailable": -1,
  "traceId": "f8e4a3b2c1d0e9f8a7b6c5d4e3f2a1b0",
  "timestamp": 1750732453635,
  "errorCode": "",
  "errorDescription": "",
  "success": true
}