Yes, that is adding controls and using a database from the SponsorBlock server.
What I mean is a plugin cannot see the video. Like you can't write
if(screen == adScreen) {
then skipToNextSegment();
}
The plugin isn't reading the video, it is getting info from a database. For AI or machine learning to work ad injection, which might change for every user, doing what SponsorBlock is doing is not enough.
I'm going to hope for the best and assume this has nothing to do with their browser. Mozilla has a lot of other products.