SUMMARY
If this is not the right place to file this bug please move it and/or let me know which Debian package this should be filed for.

After upgrading from Debian11/KDE to Debian12, plasma-systemmonitor was not installed. This should absolutely be an installed package and I think it is configured to be (as far as the logs tell, the package was installed after the upgrade on another machine when running apt full-upgrade).

On Debian11, KSysGuard was used. Now there only is KSysguard in "Background Services" which "Launches KSysguard on Ctrl + Escape" and launches systemd->systemmonitor. While this shortcut was kept, ctrl+shift+esc wasn't set anymore so one has to configure it again under "Custom Shortcuts" with command "plasma-systemmonitor".

I checked /var/log/apt/history.log and there it says "plasma-systemmonitor:amd64 (5.27.5-2, automatic)" underneath apt-get full-upgrade in the packages next to "Install: ". However that process exited with "Error: Sub-process /usr/bin/dpkg returned an error code (1)" (I think that was due to "FATAL ERROR: Both /lib/udev/mtp-probe and /usr/lib/udev/mtp-probe exist.") after which I ran "apt --fix-broken install" before running "apt-get full-upgrade" again.
Right after all this (that is upgrading to Debian12) I noticed this package was not installed and installed this specific package. Related question: how can I make sure all packages that it originally wanted to install or upgrade have been installed or upgraded?

STEPS TO REPRODUCE
1. Have a file /lib/udev/mtp-probe and a file /usr/lib/udev/mtp-probe to cause the upgrade to break in between
2. Upgrade to Debian12/KDE from Deb11/KDE with KSysguard installed at this point

OBSERVED RESULT
plasma-systemmonitor needed to get manually installed after the upgraded

EXPECTED RESULT
plasma-systemmonitor should always be installed by default on a new KDE setup as well as when upgrading from any Debian which has KSysguard installed. In addition, the shortcut ctrl+shift+esc should also be there by default and launch plasma-systemmonitor (or alternatively systemmonitor).

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian 12
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION