I don’t see myself moving away from X11; I just rely too much on the remote displaying capabilities (including connecting to a full X11 session over VNC). But I recognise that certain applications might move more and more to Wayland, so it would be nice to have a similar “best of both worlds” option under X11 as “xwayland” provides under Wayland.
Searching around for this shows I’m clearly not the only one looking for this, yet it’s almost as if the solution isn’t allowed to exist (“just make’em move to Wayland already” ?!
(Almost) every serious compositor has an option to run in an X11 window, so protocol translation is clearly possible, and implemented. That almost makes me wonder if a Wayland compositor couldn’t be implemented as an X11 extension, but here’s a less ambitious question:
Could the windowed mode of, say, KWin_wayland, be modified to use an existing X11 window rather than one it opens itself and specifically, the X11 root window or some other window created by KWin_x11 which would turn the X11-windowed mode into a de-facto rootless server?