Toward a "modern" Emacs - First Steps

Well, Firefox (or any browser really) on iOS is just a reskinned Safari. So you get syncing at least. But without the actual engine, how many add-ons actually work? But doing a vetted list of add-ons makes sense to me there. They seem to be doing something similar on Android too. For example, uBlock Origin works on Android, but Intention has not yet been allowed (I presume they do some performance metrics to avoid churning needless battery?). I also assume that they're using metrics to figure out which ones to focus on first.