For XFCE, Wayland support is developing

The experimental issues of the panel xfce4-panel 4.19.0 and desktop and desktop and desktop xfdesktop 4.19.0 , which proposes initial support in the environment based on the protocol Wayland. Support is implemented using the new library libxfce4windowing , offering layer for abstracting from a graphic subsystem capable of working on top of X11 and Wayland. The Libxfce4windowin library implemented windows control components (screens, root windows, virtual desktops, etc.), not tied to a certain window system.

Support X11 is implemented on the basis of libwnck (Window Navigator Construction Kit), and Wayland through the use of various extensions of the protocol. At the current stage of development, the implementation on top of Wayland is still lagging behind the functionality from the implementation on top of X11, since not for all X11 opportunities there are corresponding extensions of the Wayland protocol.

/Media reports cited above.