Copyright for ocaml-cairo2 source package in Focal

Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
Upstream-Name: ocaml-cairo
Upstream-Contact: Christophe Troestler 
Source: https://github.com/Chris00/ocaml-cairo
Files-Excluded: docs/
Comment:
 The header files of some source files refer to special linking exceptions
 to be found in the file LICENSE. That file, however, contains only a copy
 of the LGPL-3 license up to some minor layout changes.

Files: *
Copyright: (C) 2009 Christophe Troestler 
License: LGPL-3

Files: debian/*
Copyright: (C) 2019 Ralf Treinen 
License: LGPL-3

License: LGPL-3
 On Debian systems, the complete text of the GNU Library General
 Public License can be found in `/usr/share/common-licenses/LGPL-3'.