[sandov]

I think Fedora is the only major distro running Wayland by default. Debian and Ubuntu are still on X11.

I think Cannonical shipped 17.10 (or other minor release) with Wayland by default, but subsequent releases reverted to X11.

[raegis]

Debian Buster (which is "stable" now) defaults to Wayland in Gnome, but you can switch to Xorg at the login window, which I had to do this week for screencasting to work as expected.