When the compositor is ran on a TTY and has full control of the system resources.
In this backend the only resource the compositor uses is the Wayland file descriptor. It doesn't try to grab actual keyboard/pointers and it doesn't render anything.
When multiple backends are running or when the compositor writer doesn't care and
just used the auto create option in the
When the compositor is running in a nested Wayland environment. e.g. your compositor is executed while the user is running Gnome+Mutter or Weston.
When the compositor is running in a nested X11 environment. e.g. your compositor is executed while the user is running an X11 window manager.
A custom function to set up the renderer.