I have a theory that jarring UI changes are done as a way to measure user engagement with different browser/program/OS functions and even start analyzing someone's mental state if paired with fingerprinting data. I know that's incredibly paranoid yes, but it is logically possible.
I don't even want to leave this comment. Fediverse gets scraped by big tech the same as everything else. Can't stand this modern hellscape.
edit, my point of even leaving this comment in the first place; firefox doing this kind of thing is a pretty bad sign imo