The rationale for the licence below is -- in about this order -- that
I want the code and docs to be as free as BSD or MIT code (anyone can
use it for fun and/or profit), to be GPL-compatible whilst not being
viral (so that users aren't forced to make public things that they
would prefer were secret), to maintain copyright information like BSD
or MIT code (so that people know where it came from), and to avoid
damage to the author's or the work's reputation from 3rd party changes
like the artistic or ASF licence (except that I don't care about the
name of the package -- that's for trademark law -- or the licence
conditions of any patch).

The only really new thing is that I want to do the latter by keeping
detailed version information alongside the copyright information so
that users may know (a) when they are using a version that might
contain old mistakes, and (b) that it is not the original author's
fault that their software has not been fixed. The version information
would be a list of CVS IDs rather than a release version number so tha
interim versions may identified.

Things that I am not so sure about include:

(1) The omission of the permissions to copy and sell, and the rubric
    about "without fee" and "in source and binary forms" -- but I
    think these are implied by the licence to use, modify, and
    distribute.

(2) Whether I should say "the above copyright and version information"
    (assuming that the LICENCE file would include a cumulative
    copyright line and the CVS IDs from all of the source and
    documentation files) or should I omit the word "above"? The
    technology I use to embed the copyright, version, and licence in
    the object files may mean that what should be "above" may be
    printed out below. But is a phrasing that omits the preposition
    too general?

(3) I have greatly abbreviated the disclaimer, on the (perhaps vain)
    assumption that English law would be reasonable -- but see the
    TenDRA licence: <http://www.cse.unsw.edu.au/~patrykz/TenDRA/>. I
    worry about the loss of the capital letters (although the absence
    of their ugliness is welcome -- I assume it is an American thing),
    and the redundant phrases "without even the implied warranties of
    merchantability, fitness for purpose, and non-infingement" and the
    detailing of the damages for which I may be held liable. I don't
    think I should have to justify the disclaimer by mentioning that
    the software was made available without fee.

(4) Should I be explicit about copies of substantial parts of the
    software and/or documentation that are used to enhance other
    projects? i.e. that they should include the copyright and version
    information of the file(s) from which the excerpts came?

(5) When identifying the original file, are the authors' name(s) and
    email address(es), and the filename and version number, enough?
    Should I add a source URI? Could a URI even replace the copyright
    and version information? Even though it doesn't apply in English
    law, I see the copyright statement as an assertion of the moral
    right to be identified as the author, and replacing it with a URI
    dilutes that.

(6) Do any of the conditions conflict with the GPL? I intend to ask
    RMS about this, although his interpretation tends to be more
    strict than most. Is there a good arbitration committee of the
    Debian Free Software Guidelines?

I intend to put the licence rubric at the head of every file, which
rather highlights consideration 2, and makes brevity more important.
Does it also reduce problem 4? Could I fix that by adding "excerpt" to
the list of permissions?

Tony.
-- 
f.a.n.finch <dot@dotat.at>

/*
 * Copyright (C) 2001 Tony Finch <dot@dotat.at>
 *
 * $dotat: progetc/Doc/LICENCE.rationale,v 1.2 2002/01/15 13:44:47 fanf Exp $
 *
 * Permission is granted to use, modify, and distribute this software and its
 * documentation, provided that the copyright and version information, this
 * permission notice, and the following disclaimer appear in all copies, and
 * that modified copies are clearly marked as such and are not endorsed or
 * promoted using the name of the author without written permission.
 *
 * This software and its documentation are provided "as is", without warranty
 * of any kind: in no event shall the author be held liable for any damages
 * arising from the use of this software or its documentation.
 */