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. It's 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.

Everything else is copyright 1999-2001 by Joey Hess, under the terms of GPL.