The included themes are released under the following licenses:

desktop-themes/Darklooks:      GPL2+
desktop-themes/Unity:          GPL2+
gtk-themes/Darklooks:          GPL2+
gtk-themes/Unity:              GPL2+
icon-themes/Foxtrot:           CC-BY-SA
icon-themes/Gion:              GPL2
icon-themes/gnome-alternative: GPL2
icon-themes/Neu:               GPL2
metacity-themes/Unity:         GPL2+

A full copy of the GNU General Public License version 2 can be found in
COPYING.GPL2,
a full copy of the Creative Commons Attribution Share-Alike license version
2.5 can be found in COPYING.CCBYSA25.