I do not have that file but based on the suggestion of @deano_ferrari I did boot my machine, did Log out, change for X11 to Wayland in the Log in screen and after that I see:
> sudo cat /var/lib/sddm/state.conf
[sudo] password for root:
[Last]
# Name of the last logged-in user.
# This user will be preselected when the login screen appears
User=marel# Name of the session for the last logged-in user.
# This session will be preselected when the login screen appears.
Session=/usr/share/wayland-sessions/plasmawayland.desktop
So the last line changed, it was /usr/share/xsessions/default.desktop and now this plasmawayland.desktop file has:
[Desktop Entry]
Exec=/usr/libexec/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland
TryExec=/usr/bin/startplasma-wayland
DesktopNames=KDE
Name=Plasma (Wayland)
Unfortunately, after a reboot (initiate with Wayland active and the sddm/state.conf as above) I still boot (autologin - so no login screen) into X11. I also tried adding “RememberLastSession=true” in a /etc/sddm.conf.d/ file but still after a reboot I have X11.
Next I did check the SDDM configuration:
> cat /usr/lib/sddm/sddm.conf.d/00-general.conf
[XDisplay]
ServerPath=/usr/bin/X
SessionCommand=/usr/etc/X11/xdm/Xsession
DisplayCommand=/usr/etc/X11/xdm/Xsetup
MinimumVT=7
# boo#1089932
EnableHiDPI=true[Users]
# boo#979775
ReuseSession=true
So that is all X11, I guess I have to create a file in /etc/sddm.conf.d/ to override these settings to Wayland equivalents.