"Scroll Left" go to User Script:

mouseDown.target.scrollLeft += 60;
var result = { repeat: true };
result;

and then go to 'other gestures' enable wheel gestures, scroll UP -> 'your user script'

"Scroll Right" same as above but -=60 or whatever number of pixels you want scroll.

Dear developer. Your extension looks good, but could you please add ''Scroll Left'' and ''Scroll Right'' commands? I have a mouse with two additional buttons on its side, so I wanted to use these buttons to scroll web pages left or right.

Super!

Unfortunately it does not work well on ubuntu 22.04 since Wayland replaced X. When browser is freshly started, it works for a while, after it aprox. 15. minutes of usage it breaks and the gestures are no longer recognized, then it needs a browser restart. It's pretty annoying you're forced to restart your browser when you're in the middle of something and have a dozen tabs opened already.

Je comprends pas à quoi sa sert, pas clair...

aok