Hi Thomas, I do appreciate your work on this, it's a welcome addition! > +SPDX-License-Identifier: GPL-2.0 // GPLv2 only > +SPDX-License-Identifier: GPL-2.0+ // GPLv2 or later I am concerned about this though, as the SPDX-License-Identifier is well known to refer to the license of the document in which it appears, and it would be beneficial to avoid a situation where a tool reading this make the assumption the license text itself it under a particular license. Essentially, let's avoid overloading if we can. >From my reading, there are two intentions with the above reading: 1) To give usage guidelines and signal that for any source file, adding this exact line would be a valid license identifier, and 2) To make the license identifiers computer understandable such that tools can be updated to validate whether source code includes a license identifier which corresponds to one of the licenses in LICENSES/ I'd propose to not try to do both at the same time and would propose a 'Valid-License-Identifier' tag to meet your second criteria, and a 'Usage-Guidance' tag to meet your first one. The header would then be: Valid-License-Identifier: GPL-2.0 Valid-License-Identifier: GPL-2.0+ Usage-Guidance: To use this license in source code, you can use either of the following tags and values: . SPDX-License-Identifier: GPL-2.0 // For GPLv2 only SPDX-License-Identifier: GPL-2.0+ // For GPLv2 or any later version Best, -- Jonas Öberg Executive Director FSFE e.V. - keeping the power of technology in your hands. Your support enables our work, please join us today http://fsfe.org/join -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html