I installed the widget “comic strip” and selected four comics to be downloaded. The widget searched continuously for comics, but did not show anything but white parts of the display.

I right-clicked to see what could be the problem and selected for showing me the source or something to that effect. I do not remember exactly what I selected and I do not wish to do the installation again. Because immediately the panels disappeared and the wallpapers disappeared. The only left on the screen were the programs open in the particular activity being shown. Rebooting made no difference, Plasma was without panels and wallpaper and only the same programs showing that was there for the activity active when I rebooted.

I went with ctrl-alt-F2 to /home/[username]/ and typed the command “find . | grep -i comic” and got,

.local/share/knewstuff3/comic.knsregistry
.local/share/plasma/comics/kpluginindex.json
.local/share/plasma/comics/[four folders, one for each of the comics I had selected for download]

I removed all of the above and rebooted. Now Plasma came back to normal.

I remember the same thing, or something very similar, happened when I installed “comic strip” in Mageia 6. I think I reported it back then too. For Mageia 7, I never installed it.