Earlier quoted context omitted.
It also restored the dislike button and added support for sponsorblock (which can automatically skip sponsor segments, as well as intros, outros, "like and subscribe" reminders, non-music sections of music videos, and other fluff.) The name comes from it being an "advanced" YouTube app, only without any "ad"s ;) Oh, and you could disable the comments section! All-in-all, it just made YouTube a much better experience.
>It also restored the dislike button As a useless button to click? I would assume youtube removed the actual functionality in the backend so what's the point of the button?
(in theory, if 5% of viewers of a video are people that have the extension, and only 10% of those viewers hit the dislike button, chances are that's a good sample size to assume that this video should have a 10% dislike ratio, but in practice it's probably a bit more complicated/weighted)