Kubuntu upgrade

[Ralf Mardorf]

Hi,
you are running Muffin, the window manager of Cinnamon. "Cinnamon does
not support using a different window manager."[1] and "It cannot be used
outside of Cinnamon."[2] It "is a Wayland display server and X11 window
manager and compositor library. [...] When used on top of Xorg it acts
as a X11 window manager and compositing manager."[3]

Since Muffin (a fork of Mutter [4]) cannot be used outside of Cinnamon,
we now know without any doubts, that you are running a Cinnamon session
on top of X, hence it's not a KDE session with some weird thing going
on. It does not help us to know why Cinnamon was installed and became
the default desktop environment. Likely the last installed desktop
environment becomes automatically the default. Maybe Liam's guess is
true.

When installing a package different kinds of dependencies do exist,
"depends recommends suggests enhances". AFAIK by default "depends" and
"recommends" get installed, while "suggests" don't get installed by
default, "enhances" is new to me, probably a subdivision of "suggests".

Maybe you changed it to automatically install suggested packages, too
and this maybe is the reason that Cinnamon was installed by an update.

Regards,
Ralf

[1]
https://wiki.archlinux.org/title/Cinnamon#Use_a_different_window_manager
[2]
https://wiki.archlinux.org/title/window_manager#Stacking_window_managers
[3]
https://github.com/linuxmint/muffin/
[4]
"Muffin is a fork of Mutter by the Linux Mint team for their Cinnamon
desktop environment. Cinnamon's shell, a fork of GNOME Shell, is written
as a plugin for Muffin." -
https://en.wikipedia.org/wiki/Mutter_(software)#Forks