License header

FreeMind uses the following license header in .java files (see also Licensing):

/* FreeMind - A program for creating and viewing mind maps
 * Copyright (C) 2000-<YEAR> <AUTHORS>
 * See COPYING for Details
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

Questions:

• What detail and granularity of authorship should be maintained in the license header?
• Would it suffice to identify the license more succinctly, e.g. "License: GNU GPL V2+; see COPYING for details"? For instance, the applicable SPDX license identifier is "GPL-2.0-or-later"[1].
  • What FOSS projects use this kind of succincts identification?
  • What FOSS projects use SPDX identifier and in what way?

Example author-declaring lines in the license headers of FreeMind 0.9.0:

• Copyright (C) 2000-2001 Joerg Mueller <joergmueller@bigfoot.com>
• Copyright (C) 2000-2006 Joerg Mueller, Daniel Polansky, Christian Foltin, Dimitri Polivaev and others.
• Copyright (C) 2000-2006 Christian Foltin and others
• Copyright (C) 2000-2004 Joerg Mueller, Daniel Polansky, Christian Foltin and others.

Helpful queries using Unix-like oneliners:

• grep -r --include="*.java" "Copyright" .
• grep -h -r --include="*.java" "Copyright" . | sort | uniq
• grep -h -r --include="*.java" "Copyright" . | sed "s/.*\(C\).*[0-9] *//" | sort | uniq

  This one drops the beginning with years and year ranges.

Example author-declaring line in Emacs[2]:

• Copyright (C) 2023-2026 Free Software Foundation, Inc.

Notes: the license header resembles that of FreeMind. GNU Emacs requires copyright assignment to FSF, making the above possible.

Example license header from Linux[3]:

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  kernel/sched/core.c
 *
 *  Core kernel CPU scheduler code
 *
 *  Copyright (C) 1991-2002  Linus Torvalds
 *  Copyright (C) 1998-2024  Ingo Molnar, Red Hat
 */

Keywords: copyright header, copyright notice.

Links:

• https://www.linuxfoundation.org/blog/blog/copyright-notices-in-open-source-software-projects