Yes, that's because the window managers implemented this themselves because Wayland didn't. So that means most window managers use wlroots to provide the functi

Yes, that's because the window managers implemented this themselves because Wayland didn't. So that means most window managers use wlroots to provide the functionality, and a few (KDE/Gnome) are doing their own thing. This also means that if you want to interoperate with them it's different for each window manager (that doesn't use wlroots). Things are somewhat usable now thanks to this, but far from ideal.