>>As it happens in the open source world, some disagreed and... ever since then I'm using https://www.waterfox.net/ - a different branch which feels like Firefox should, and it just works.
>
>Firefox is pretty open about what they do. ISTR there were good technical reasons for that change, and the add-ons I use adapted to it.

And the guys at Waterfox disagreed and the add-ons just kept on working in it.
That being said, I discovered that I've ditched more than half the add-ons I once used. I remember having quite a few - image zoom, mouse gestures, clocks for various timezones, makelink. Now there's just a few left, the ones I regularly use: stylish, for one, because I found I read serif fonts more easily, so on the both forums (here and a local one) I see everything with serifs. And, of course, adBlock+.