XFCE developers have announced plans to add support for the Wayland protocol in the upcoming XFCE 4.20 release. The plans were shared on the XFCE Wiki page. The next major release will include the implementation of initial Wayland support while still maintaining support for X11. Previously, there was a discussion around maintaining reverse compatibility with X11, but it has now been decided that X11 support will continue in the future.
The Wayland Session in XFCE 4.20 will initially cover the minimum necessary set of capabilities. The developers plan to gradually add missing functionalities in subsequent releases. They also intend to refine the work surrounding the Wayland protocol in already ported user applications.
In terms of composite managers for Wayland, the project has decided not to develop its own and has rejected the possibility of using a binding to XWayland. Instead, they have chosen to use the wlroots library developed by the SWAY user environment developers. This library offers basic functions for organizing the work of a composite manager based on Wayland.
Some components of XFCE, such as xfdesktop and XFCE4-Panel, have already been ported for Wayland and continue to be developed as separate components. The XFCE4-Panel has been tested with composite Labwc and Wayfire servers. To abstract work on top of Wayland and X11, the libxfce4windowing library is used. This library provides a layer for abstracting the graphic subsystem and implements components for controlling windows, screens, root windows, virtual desktops, etc., that are not attached to a specific window system. X11 support is implemented using the libwnck library