Preface: This issue is not about relicensing alpaka or stripping people / institutions of their (copy)rights. Its purpose is simply to be a clarification of the current legal state.

While working on #1917 I saw that the SPDX specification makes a distinction between copyright and authors. After a longer discussion in yesterday's VC I looked into the relevant legal frameworks for Germany (I believe this works more or less the same for all countries as well as CERN's special law) and arrived at this conclusion:

• An author is always a (human) person. An author can never lose this status or transfer the author rights to someone else (except when the author dies). If multiple people work on the same project they are equal co-authors. By default German law also assigns the copyright to the (co-)authors.
• Copyright is the right to economically exploit a project, i.e. copy / distribute / sell it to third parties.
• In the case of employed software developers, German law makes an exception to the first point: The copyright is automatically transferred to the employer unless the contract explicitly states something else.

(Sources for the Germanophone crowd: §7, §8, §69b UrhG)

In my understanding, this means that our copyright information at the beginning of each source file is wrong:

/* Copyright 2022 Axel Huebl, Benjamin Worpitz, Erik Zenker, Matthias Werner, René Widera, Bernhard Manfred Gruber,
 *                Jan Stephan, Antonio Di Pilato
 * SPDX-License-Identifier: MPL-2.0
 */

and should be changed to:

/*
 * Copyright 2023 Helmholtz-Zentrum Dresden-Rossendorf e.V.
 * Copyright [year] CERN
 * Copyright [other year] TU Dresden
 * Copyright [another year] Benjamin Worpitz // example for someone who works on alpaka privately
 * Authors: Axel Huebl, Benjamin Worpitz, Erik Zenker, Matthias Werner, René Widera, Bernhard Manfred Gruber,
 *          Jan Stephan, Antonio Di Pilato
 * SPDX-License-Identifier: MPL-2.0
 */

Or, if we want to do this conforming to SPDX:

/*
 * /*
 * SPDX-License-Identifier: MPL-2.0
 * SPDX-FileCopyrightText: 
 *    - 2014 - 2023 Helmholtz-Zentrum Dresden-Rossendorf e.V.
 *    - 2019 - 2023 CERN
 *    - [other institutions / private persons]
 * SPDX-FileContributor: Benjamin Worpitz
 * SPDX-FileContributor: René Widera
 * SPDX-FileContributor: Bernhard Manfred Gruber
 * [and so on]
 */

What do you think? @alpaka-group/alpaka-maintainers