SPDX-License-Identifier: LicenseRef-NKlein-Universal-NonExclusive
SPDX-FileCopyrightText: 2000-2002 Patrick Stein / nklein software

This is a non-standard, custom license, transcribed verbatim from the
copyright/license page nklein software published at its own site-wide
`etc/copyright.php`, which the 54321 product page (preserved unmodified in
this repository under reference/54321-1.0.2001.11.16/data/webpage/hdr.php
and tail.php) included as its own shared header/footer.

Verified against archived captures of the live page:

  - https://web.archive.org/web/20010613000000/http://www.nklein.com/etc/copyright.php
    (13 Jun 2001 — five months before 54321's 16 Nov 2001 release; page footer: "(copyright 2000)")
  - https://web.archive.org/web/20051226000000/http://www.nklein.com/etc/copyright.php
    (26 Dec 2005; page footer: "(copyright 2002)"; text identical except for one added parenthetical exempting xhtml/css/paypal icons)

Both captures carry materially the same operative text, reproduced below
from the 13 Jun 2001 capture (the one that predates the 54321 release):

----------------------------------------------------------------------

Copyright:

We made all images, text, software, and other stuff on this web site.
We authorize you to do anything you like with these so long as you do
not restrict the rights of others to do what they like with them.
We're not saying you have to give away your products. We're just
saying that all of the items on this site have a Universal,
Non-Exclusive License.

For example, if you wanted to take some of these images or some of
this software and plaster your name on them and sell them, fine. But,
you cannot keep Sally Q. Public from taking those same items and
plastering her name on them and selling them. You just can't. It's
all as hers as it is yours.

All of that said, it'd please us plenty if you slung appreciation,
accolades, credit, and/or cash our way as you see fit.

----------------------------------------------------------------------

Independent corroboration: LibreGameWiki (https://libregamewiki.org/54321,
retrieved 2026-09-12) classifies 54321's code and media as "a very simple
copyleft license", cites this exact URL as its reference, and states "the
source code and media files are available to be studied, modified, and
distributed."

See ../PROVENANCE.md, ../docs/LICENSE-RESEARCH.md and
../docs/archaeology/LEGAL_STATUS.md for the full evidentiary chain and how
this license interacts with this repository's own GPL-3.0-or-later code.