This is a Debian prepackaged version of the filters package.

This package was put together and debianized by Joey Hess
<joeyh@debian.org>, using sources from
	http://qz.to/~eli/src.html and
	ftp://ftp.funet.fi/pub/misc/old-hsu-archive/unsorted/2/kraut.shar.gz

The jethro filter has this copyright:
  **   Public domain. Use at your own risk. Y'all come back now, heah?

The kraut filter has this copyright:
  /* Kraut v0.9  */
  /*     by      */
  /* John Sparks */
  /*  5-5-1989   */

  /* This is in the public domain. Do with it as you will. *\

The cockney, jive, and nyc filters are copyright under the GPL by Daniel V
Klein. He confirmed the new copyright in this email:

  From: Daniel V Klein <dvk@lonewolf.com>
  Date: Wed, 22 Nov 2000 22:00:50 -0500
  To: Joey Hess <joey@kitenet.net>
  Subject: Re: filters GPL'd 
  
  That is so.  Have fun (FWIW, I have done some rewriting on them - they are
  now in Perl, but still need some work...)
  
  -Dan
  
  > I've been told that you have changed the copyright of the cockney, jive
  > and nyc filters to the GPL? Is that correct? I'd love to move them into
  > Debian proper.

The rasterman filter was pulled out of
http://www.xach.com/xachbot/xachbot-2000-07-15.tar.gz, which is as a whole
copyright (C) 1997 Zachary Beane and is GPL'd.

The ken filter is now in the public domain. Its author, Stephen K Mulrine,
confirmed the new copyright in this email:

  From: Stephen Mulrine <stephen@moroder.scotnet.co.uk>
  Date: Mon, 11 Jun 2001 01:06:52 +0100 (BST)
  To: edward@debian.org (Edward Betts)
  Subject: Re: Ken?

  [...]

  >We would like to include ken in the Debian GNU/Linux Operating System, but
  >we need permission to modify ken if we want to. Would you be willing to
  >relicense ken under the GNU GPL, a BSD like license, or public domain?

  Certainly, it would be an honour to have it included in the Debian
  distribution so I hereby release ken into the public domain.

The ky00te filter is now relicensed under the GPL. Its author, Brent
Edwards, confirmed the new copyright in this email:

  From: Brent Edwards <chipuni@hypersurf.com>
  Date: Sat, 30 Jun 2001 09:37:53 -0700
  To: Edward Betts <edward@debian.org>
  Subject: Re: Is this the author of the ky00te filter?

  Dear Edward,
          You have my permission to put the ky00te filter into the GNU GPL
  license.  (Though the license will be far longer than the program itself!)

                          -- Brent Edwards

Everything else is copyright 1999-2001 by Joey Hess, under the terms of GPL.
The full text of the GNU GPL can be found in /usr/share/common-licenses/GPL
on Debian systems.