VSCode (or the base app used by it) is open source (see: VSCodium). It has a similar relationship to Chrome and its base Chromium, where assets and tweaks are added to brand the product. You may have been trying to say “a great open source, VSCode alternative” and I misunderstood. Just commenting to remove ambiguity.
Liking and commenting isn’t possible through any client to my knowledge. Freetube is a nice frontend app available on linux. Follow existing tutorials for how to export subs from YT then import your subs in the app.