Copyright for newpid source package in Focal

Author, Copyright, and Debianization:
  Copyright 2013-2015 Christoph Berg  GPL2+
get_ctl_fd, do_chflags, netns_switch functions from iproute2:
  Copyright Alexey Kuznetsov  GPL2+

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.

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