I don't know whether it is relevant or not and whether it helps anyone understand the practical aspects of it all. If you start a wayland session, wlroots, wm, .. inside an X environment, and run xrandr/arandr in it through Xwayland it shows as the monitors available being X11 (that's how Xrandr identifies the screen it is called to modify). If on another tty you start a true wayland session and within it run xrandr/arandr it identifies the true monitors (hdmi1 dp2 .. whatever) but if you attempt to alter resolution/size it fails, even though an X session is running inside the same system. wlr-randr or something similar can and affects the true wayland session. Whether it is the protocol, how the environment is set, whether it is a matter of authority to modify output ..
One thing that makes me scratch my head is how for years distro people were saying that is not secure for a user to own/start an X server, it should be a root or other higher authority starting and then the user can run things within it. But if you made the conscious decision to oversee those security "issues" and were able to start as user, you felt a bit uneasy as doing something wrong. With wayland, if a seat daemon provides a seat to the user, the user can start several sessions. Another matter, I see avoidance of mentioning the word wlroots .. is there a functional alternative to it? I haven't found one.
