SUMMARY
I installed openSUSE Tumbleweed with Plasma Krypton repositories and System
Settings failed to show the contents of several KCMs (Global Theme, Plasma
Style, Colors, Icons etc) that depend on KNewStuff, stating that a newstuff
library was missing.

It also broke the wallpaper settings (Wallpaper type: Image) on Wayland and
Full Wayland, as it did not display the images selection pane.

>From what I gather, systemsettings5 should pull knewstuff-imports as a main
dependency. YAST did not pull it even when enabling recommended packages.

SYSTEM
Operating System: openSUSE Tumbleweed 20200128
KDE Plasma Version: 5.18.80
KDE Frameworks Version: 5.67.0
Qt Version: 5.14.1
Kernel Version: 5.4.14-1-default
OS Type: 64-bit
Processors: 4 �� Intel�� Core��� i5-7200U CPU @ 2.50GHz
Memory: 15,5 GiB