This JSON file is used with Obsidian's Web Clipper to convert YouTube embeds and subtitles into a Markdown file.
Click on "...See more" under the YouTube video. Then, in the "Transcript" section, click on "View Transcription".
Please refer to the image below. (Apologies for the Japanese screenshot.)
In English, it looks like this:
After that, please clip it with the Obsidian Web Clipper.
The result will be as follows.