This is Ubuntu GNU's GnuPG keyrings of archive keys.

This package was originally put together by Michael Vogt
<michael.vogt@canonical.com> 

The keys in the keyrings don't fall under any copyright.  Everything
else in the package is covered by the GNU GPL.

Ubuntu support files Copyright (C) 2004 Michael Vogt <michael.vogt@canonical.com> based on the debian-keyring package maintained by James Troup 

This package was modified by Rubén Rodríguez <ruben@trisquel.info>

Copyright (C) 2010 the authors

  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.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

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