As I've replied to many - the extenion didn't change - Mozillas processes changed.

"Personal data" mentioned - is the random user id used to count likes and dislikes
"Browsing activity" = detecting that you navigated to the next video to show you the dislikes for the next video
"Website activity" - clicking likes and dislikes.

This is how the extension worked from the day one - but now Mozilla requires explicit user consent for this. And they do it on update release - which makes users think that something in the extension changed.