Comment by kelnos

(xfwl4 author here.)

I spent a month or so in 2024 attempting to refactor xfwm4 so it could serve dual purpose as both an X11 window manager and Wayland compositor, and ended up abandoning the idea. It was just getting ugly and hard to read and understand, and I wasn't confident that I could continue to make changes without introducing bugs (crashers, even). We want X11 users to be unaffected by this, and introducing bugs in xfwm4 wouldn't achieve that goal.

Note that we don't have to rewrite all of Xfce: xfce4-session, xfce4-panel, xfdesktop, etc. will all run on Wayland just fine (there are some rough edges that need to be ironed out for full Wayland support, but they're already fairly usable on wlroots-based compositors). This is just (heh, "just") building a compositor and porting xfwm4's WM behavior and UI elements over to it. Not a small task, to be sure, but much smaller than "rewriting all of Xfce".