MISC resources regarding licensing.
List of SPDX License Identifiers
https://spdx.org/licenses/
Re-using free software via writefreesoftware.org
https://writefreesoftware.org/learn/participate/derived-works/
Chossing a license via writefreesoftware.org
https://writefreesoftware.org/learn/participate/choose-a-license/
REUSE Specifications
https://reuse.software/
Intra-GPL compatibility matrix via gnu.org
https://www.gnu.org/licenses/gpl-faq.html#AllCompatibility