Kbuildsycoca5: `Service type not found`

So, while working on something unrelated (trying to create a desktop entry for an appImage), I got the following warning message from kbuildsycoca5 --noincremental:

kbuildsycoca5 running...
kf.service.sycoca: Service type not found: "application/x-cmakecache

Yes, I know it’s only a warning, but it’s really bugging me.

xdg-mime seems to understand that type:

xdg-mime query default application/x-cmakecache
cmake-gui.desktop

And a filesystem search shows it’s being defined (I think?) in cmake-gui:

rg cmakecache /usr/local/
/usr/local/share/applications/mimeinfo.cache
2:application/x-cmakecache=cmake-gui.desktop;

/usr/local/share/applications/cmake-gui.desktop
12:MimeType=application/x-cmakecache;

/usr/local/share/mime/packages/cmakecache.xml
3:  <mime-type type="application/x-cmakecache">

I’ve tried various invocations of update-mime-database to no effect, kbuildsycoca6 doesn’t help, and removing the cache under ~/.cache/ksycoca5* doesn’t help either. I’m not if this is a bug in cmake-gui, kservice, or something else. Anyone got any ideas?

What OS are you using? Is it KDE Linux, or something else?

Ah, sorry, should have specified, this is fedora 43:

uname -a
Linux rook.nest 6.19.11-200.fc43.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Apr  2 16:55:52 UTC 2026 x86_64 GNU/Linux

kbuildsycoca5 -v
kbuildsycoca5 5.116.0