All of this is for Firefox: Linux has support for touchpad pinch zoom, at least under Wayland. Not sure if it's still gated behind an about:config user pref or

All of this is for Firefox: Linux has support for touchpad pinch zoom, at least under Wayland. Not sure if it's still gated behind an about:config user pref or not. If you don't have a touchpad, I'm pretty sure you can bind "pinch zoom" to <modifier key>+<mousewheel>. I think the about:config preference is `mousewheel.with_alt.action=5` (or `with_shift`, etc). As for "pinch zoom" using the keyboard, I'm not sure. I don't believe there's any extension API for it. A check of the Mozilla bug tracker didn't bring up anything.