On Debian systems, the full text of the CC0 1.0 Universal License
can be found in the file `/usr/share/common-licenses/CC0-1.0'. 

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 3 of the
License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

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

On Debian-based systems, the full text of GPL-3 could be found at
/usr/share/common-licenses/GPL-3 .