This is Debian GNU/Linux's prepackaged version of xsok.
xsok was written by Michael Bischoff <Michael.Bischoff@gmx.net>.

The upstream source was downloaded from

ftp://ftp.io.com/pub/mirror/FreeBSD/ports/distfiles/xsok-1.02-src.tar.gz

Current Debian maintainer: Joel Rosdahl <joel@debian.org>

    This program is free software; you can redistribute it and/or modify
    it 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.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details. (The file COPYRIGHT.GNU)

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
    02111-1307, USA.

On Debian GNU/Linux systems, the complete text of the GNU General
Public License can be found in `/usr/share/common-licenses/GPL'.
