So, what sorcery has OpenSUSE managed in the Plasma Wayland session? In particular, this is in relation to Zoom screen sharing options. Under Wayland (on other distros), I cannot share any KDE/Qt windows, only GTK ones. However, in the Wayland session of openSUSE (not Full Wayland), I can share all windows open. even if I cannot share screens (for now).
Please help me understand what settings/env vars are set during the Wayland session. I have already looked at
/usr/share/wayland-sessions/plasmawayland.desktop
and cannot find anything that helps. The only difference seems to be that plasmafullwayland.desktop has the following Exec line:
Exec=env GDK_BACKEND=wayland QT_QPA_PLATFORM=wayland /usr/lib64/libexec/plasma-dbus-run-session-if-needed
However, that does not help to understand why “partial” wayland allows sharing of all windows 
Confused? Me too. Hopefully someone can help. Thanks.
Partial Wayland starts wayland composer (allowing you to run native wayland clients) but makes Qt/Gdk toolkits default to X11, so you session applications effectively run as X11 clients under Xwayland X server.
Full Wayland forces toolkits to use wayland so your session applications run as native wayland clients and there is no native screen sharing in Wayland. It requires additional software and protocols (like pipewire/xdg portal) and it is up to each client and desktop environment to implement them. GNOME provides implementation and as far as I know Zoom supports screen sharing under GNOME. I do not know about KDE.
Thanks. So, would it be possible to “replicate” this behaviour on other distributions using environment variables only or is something deeper that openSUSE has baked in to this session?
Yes, it should be possible. Although you may be interested in recent thread on factory mailing list which requested to remove this artificial separation and leave just one default Wayland session, claiming that setting of these variables results in various buggy behavior. The OP pointed at “other distributions” which do not have these two types of sessions 
… found it. Please remove the xwayland ("Wayland") and wayland ("Full Wayland") sessions as we know them - openSUSE Factory - openSUSE Mailing Lists