arbitrary mouse (or "mouse") button remapping in libinput (my understanding is that libinput itself supports it, but due to some security-related reasons it has

arbitrary mouse (or "mouse") button remapping in libinput (my understanding is that libinput itself supports it, but due to some security-related reasons it has to be configured on behalf of the logged-in user and the UI is just not there, or something). the upshot is that I cannot use my trackball the way I'm used to, and that seriously sucks.