Displays an incomplete set of the lyrics below the video in black, which makes it a) badly positioned, b) unreadable when using the official YT dark theme, or any other sort of third party dark YT theme, and c) pretty unreliable when it is missing half of the remaining lyrics of the song.
There is also a "load more" link below the lyrics, which open a lyrics.com tab of a completely different song.

I hope this also working on https://music.youtube.com

It doesn't work for me. 30% of the lyrics text is loaded using the musixmatch API, but it is not rendered below the video. Sounds promising, but doesn't work. I also would like an option to retrieve the lyrics automatically.