Xfce 4 is copyright Olivier Fourdan <fourdan@xfce.org>. The different components are copyrighted by their respective authors.
The packages libxfce4util and xfprint are distributed under the terms of the BSD license.
The libxfce4mcs and libxfcegui4 libraries and the xfce-mcs-manager package are distributed under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
The packages xfce-mcs-plugins, xfce-utils, xfce4-panel, xfce4-session, xfdesktop, xffm and xfwm4 are distributed under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.