"Long overshadowed by its GNOME and KDE-based brethren, Xubuntu
is a handy Ubuntu solution for older PCs or for users that want a
lighter desktop footprint.
"Xfce has changed a great deal over its history; originally
intended to be a CDE-clone, Xfce has morphed into a GTK+-based
desktop that is best explained to neophytes as "Gnome-lite". Some
of the GNOME applications that you would be used to have been
replaced in Xfce, presumably to maintain the smallest footprint