Your report says Firefox gestures are working on Wayland, and two finger swiping left/right appears to be configured in the Firefox prefs to go back/forward in history:
However, Firefox doesn't respond to these gestures. Do you know what's up with that? (I'm on Fedora 35, if that's relevant.) Two finger scrolling up/down works just fine.
Interesting, this feature may only be for touchscreens because two-finger swipes are registered as scrolls on Wayland. This will indeed need further work.
What does work though is two-finger pinch gesture to zoom in/out of a web page.
IIRC these weren't for two finger swipes at least on macOS (which is the only place I saw this working). I think these were handling 3-finger swipes. Unfortunately now GNOME chomps 3-finger swipes so IDK if that is where the problem is (I guess someone without GNOME can try and see).
Your report says Firefox gestures are working on Wayland, and two finger swiping left/right appears to be configured in the Firefox prefs to go back/forward in history:
However, Firefox doesn't respond to these gestures. Do you know what's up with that? (I'm on Fedora 35, if that's relevant.) Two finger scrolling up/down works just fine.