I wanted to install a new font (dolphin double-click file) and got:
First I assumed the font file was corrupted, but it happens with every font file. Then I noticed that the Font Management panel in Settings was missing. The CLI says:
$ kcmshell5 --list | grep font
fontinst - Install, manage and preview fonts
kcm_fonts - Configure user interface fonts
$ kcmshell5 fontinst
"fontinst" should not be loaded.
Could not find module 'fontinst'. See kcmshell5 --list for the full list of modules.
Everything is up to date:
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2
Kernel Version: 5.10.6-zen1-1-zen
The Font Manager also doesn’t show up in plasma Settings at all. It’s just the one Fonts panel where you set the plasma defaults instead of an arrow indicating subentries (Fonts and Font Manager):
Advancing that idea: I install fonts for my user, that’s why I noticed the issue in the first place. But a newly created user without any additional fonts is also affected.