Gnome has built in gestures for the 4-finger swipe, but they can also be extended to more 3/4-finger gestures by e.g. https://github.com/mpiannucci/gnome-shell-extended-gestures. But they only work on Wayland but not XOrg. On the other hands, a 2-finger scroll works no matter which display server protocol is used.
I was wondering about why this is the case. Why does this depend on the display server protocol? What are the technical insights behind this?
Two-finger scrolls are usually interpreted by the input driver and sent as a motion event with a scroll axis; clients never see the swipe gesture, they only receive the scrolling motion.
There is no support in the XInput2 protocol for touchpad gestures with two or more than two touch points, like swipe and rotate. In order to support them and send them to clients you’d have to implement a new version of the XInput2 protocol, something that nobody has done, and that nobody (who is remotely qualified) is planning to do.