There's a reason why it's a good idea to add the full license to the top of the files, and that is due to the fact there can be ambiguity as to future submissions and to the current license.
The use of the term "or" in the header gives the assumption that licensing can remain somewhat lax, and just for the sake of comfort, I'd say it'd be a better idea to include the preamble.
Since with some of the code I have uploaded to the SVN, it is completely different to that of the PukiWiki that currently exists, and was written entirely by me - I have mandated that any editions maintain the header in the file.
GPL v2 or (at your option) any later version
Since there are considerable differences between GPLv3, it'd be wise to implicitly define GPL2 and then give the option of re-licensing under GPLv3 so long as there is compatibility with the previous author and those wanting to move to GPLv3. Still - it is very messy to have lots of different licenses and permutations thereupon, why even bother?
PROPOSE CHANGE OF:
// PukiWiki - Yet another WikiWikiWeb clone // $Id: convert_html.php,v 1.18 2006/05/13 07:29:58 henoheno Exp $ // Copyright (C) // 2002-2005 PukiWiki Developers Team // 2001-2002 Originally written by yu-ji // License: GPL v2 or (at your option) any later version
PukiWiki - Yet another WikiWikiWeb clone. Copyright (C) 2002-2008 PukiWiki Developers, 2001-2002 yu-ji (For a list of developers, please see blah.com/blah) 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.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
License: GPL version 2, or (at your option) any later version