Wallpaper config is not only loaded in plasma but also int the screenlocker kcm Image, SlideShow: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/config.qml:13 module "org.kde.plasma.plasmoid" is not installed
I can only reproduce with the Screen Locking kcm, on the Plasma dialog it looks just fine. Also I wonder where the error is coming from since the module is obviously installed as it's used all over the place.
Indeed, just in the KCM.
I assume the module is only a virtual one, i.e. added runtime by something in plasma-framework with qmlRegister*. And the kcm doesn't do anything plasma
Moving to kscreenlocker as the broken code is there.
https://invent.kde.org/plasma/kscreenlocker/-/merge_requests/66
Git commit 56746387dae2c125e9fc593227f7f3b73ba07096 by Aleix Pol. Committed on 21/04/2022 at 00:04. Pushed by davidedmundson into branch 'master'. kcm: Fix the load of wallpaper kcms Wallpaper kcms use sometimes the Plasmoid object (conditionally) to check some parameters. Recently, we ported from the old "plasmoid" context to the Plasmoid attached property coming from org.kde.plasma.plasmoid. This needs to have its import available otherwise QML rightly refuses to load anything. This includes the import by only registering a dummy empty object so it doesn't complain anymore. M +5 -0 kcm/kcm.cpp https://invent.kde.org/plasma/kscreenlocker/commit/56746387dae2c125e9fc593227f7f3b73ba07096