As part of the Red Hat led effort for making XWayland's rootful mode more useful and the ability to run X11 desktop sessions within XWayland as part of RHEL 10 dropping the X.Org Server support besides XWayland, a new "-output" option was added to XWayland for better control over placement of rootful fullscreen windows.

Olivier Fourdan with Red Hat has contributed to upstream XWayland a "-output" command line argument for allowing the placement of the XWayland rootful fullscreen to be placed. The "-output" argument supports a monitor name as defined by the Wayland outputs. This option makes it possible to specify a given output/monitor where wanting to run a rootful fullscreen window such as for a classic X11 desktop and even the ability to run multiple XWayland rootful fullscreens on multiple outputs.

-output name

Specifies on which output Xwayland fullscreen rootful should be placed. The name must match the name of an existing Wayland output (output names can be found using wayland-info).

If no matching output can be found, the Wayland compositor will decide on which output the fullscreen rootful Xwayland window will be placed.

This option has no effect if Xwayland is running rootless.

This XWayland -output option was committed today to the X.Org Server Git tree. See this merge request for more information on the new XWayland output option.