According to https://bugs.kde.org/show_bug.cgi?id=343418#c16 , a packaging problem in kdelibs5-plugins (which contains compatibility plugins) might be the culprit.
According to https:/ /bugs.kde. org/show_ bug.cgi? id=343418# c16 , a packaging problem in kdelibs5-plugins (which contains compatibility plugins) might be the culprit.