I hate being the poo pooer who says that subtitles are available via the API and wish the tool went that route.

I'm all for stuff being archivable with tools like youtube-dl, but I much prefer to see tools like this use the API despite its quotas because it goes beyond archiving a copy for reference. Tools that (ab)use scraping only justify anti-scraping efforts that journalists and the like use and escalate that arms race. I think one could still scrape a channel or two per day within API usage limits [1]--50 units per list, 200 units per download; quota 10,000 units per day.

[1]: https://developers.google.com/youtube/v3/docs/captions/downl...