This is Debian GNU/Linux's prepackaged version of xsok. xsok was written by Michael Bischoff . The upstream source was downloaded from ftp://ftp.io.com/pub/mirror/FreeBSD/ports/distfiles/xsok-1.02-src.tar.gz The current Debian maintainer is Peter Samuelson . Much of the packaging work was done by previous Debian maintainers Sven Rudolph and Joel Rosdahl. Copyright (c) 1994 by Michael Bischoff (mbi@mo.math.nat.tu-bs.de) 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., 51 Franklin St., Fifth Floor, Boston, MA 02110-1301, USA. On Debian GNU/Linux systems, the complete text of the GNU General Public License version 2 can be found in '/usr/share/common-licenses/GPL-2'.