Most browser extensions seem to be used on Firefox, because Google is so hostile to ones on Chrome. With the decline of Firefox, the extension world has shrunk. I had something called "Ad Limiter" on both Firefox and Chrome for a decade. Identical code, even. Google sent me threatening messages last year, as they tightened the screws on ad blockers, and I dropped it for Chrome.
Firefox is not really less hostile now. You can't even install and maintain local add-ons anymore. You can either install them temporary, and they are removed when the app closes. Or you must upload and sign them to their store.
I believe nightly edition and/or developer edition lets you install unsigned addons. Also there's a way to get an addon signed for private non-store use - can't speak to how that works, as my current project isn't quite to that stage yet.
That's a good point. Perhaps Firefox will benefit from an embrace/extinguish maneuver for once. Become compatible with Chrome extensions, then take over the space as Google retreats. This path too passes through no longer referring to "browser extensions".
