Xdelta3 was designed and implemented by Joshua MacDonald.

Xdelta3 was downloaded from http://xdelta.org/
but the file draft-korn-vcdiff.txt was deleted
from the original tar file, since it is not freely redistributable.

Copyright:
  XDelta3 - A binary delta generator.
  Copyright (C) 2001, 2003-2016.  Joshua P. MacDonald

  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, a copy of the GNU General Public License is available
  in /usr/share/common-licenses/GPL.
