These endpoints require passing a JSON payload. To allow twit to support these endpoints, the subtitle endpoints need to be added to the JSONPAYLOAD_PATHS variable in twitter.js. In addition, to upload subtitles via the chunked media upload, the media_category must be set to "SUBTITLES".
As of late May, users can create and delete subtitles via the Twitter API.
https://developer.twitter.com/en/docs/media/upload-media/api-reference/post-media-subtitles-create https://developer.twitter.com/en/docs/media/upload-media/api-reference/post-media-subtitles-delete
These endpoints require passing a JSON payload. To allow twit to support these endpoints, the subtitle endpoints need to be added to the JSONPAYLOAD_PATHS variable in twitter.js. In addition, to upload subtitles via the chunked media upload, the media_category must be set to "SUBTITLES".