SUMMARY
plasma-login-wallpaper shows only a black screen when used with current master branch of libplasma. Probably caused by https://invent.kde.org/plasma/libplasma/-/commit/c7e0ba9bb929c0bc6817cc676235d036f5ac04da

QFSFileEngine::open: No file name specified
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:52: TypeError: Value is null and could not be converted to an object
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:62: TypeError: Cannot read property Blur of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:61: TypeError: Cannot read property Color of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:60: TypeError: Cannot read property FillMode of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:88: TypeError: Cannot read property UncheckedSlides of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:87: TypeError: Cannot read property SlideshowFoldersFirst of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:86: TypeError: Cannot read property SlideshowMode of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:85: TypeError: Cannot read property SlideInterval of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:84: TypeError: Cannot read property SlidePaths of null
file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:67: TypeError: Cannot read property PreviewImage of null

STEPS TO REPRODUCE
1. Build plasma-login with master libplasma

OBSERVED RESULT
Only a black screen is displayed instead of the expected wallpaper.

EXPECTED RESULT
The wallpaper should render properly on the login screen.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: 
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION