Copyright for diffpdf source package in Bullseye

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: DiffPDF
Upstream-Contact: Mark Summerfield 

Files: *
Copyright: © 2008-2012, Qtrac Ltd.
License: GPL-2+

Files: debian/*
Copyright: © 2009-2012, David Paleino 
License: GPL-2+

License: GPL-2+
 This package 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 package 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 package; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
Comment: on Debian systems, the complete text of the GNU General
 Public License version 2 can be found in `/usr/share/common-licenses/GPL-2'.