If you used an older ISO that used to use XFCE as the base DE in an offline install and then later removed it and installed KDE this would be where the packages came from.
-m, --foreign
Restrict or filter output to packages that were not found in the sync database(s).
Those packages seem to have been part of your original offline install.
Apparently they have been dropped from endeavouros repo and that is why they show as foreign packages.