How do we deal with multiple licences in an Eclipse project repository?

Ideally, all content in a repository should be under a single licence. In this case, the repository will have a LICENSE file in the root that contains the full text of the licence, and every file will have a copyright and licence header that expresses the licence in human-readable text and SPDX expression (as described in the handbook).

Ideally, the repository should express the licence information for every file. This is difficult/impossible for some types of files (e.g., JSON files). We recommend that projects consider adopting REUSE.software.

It is common for Git repositories to contain some content under different licences. Project documentation may be managed under a licence that's different from code. Ideally in this case, content under a different licence should be grouped together (e.g., under a doc directory) to make the nature of the licence of specific content as obvious as possible to adopter. Documentation (e.g., Asciidoc or Markdown files should have copyright and licence file headers like all other content).

Templates and examples are examples of other content that might be distributed under licences that are different from the project/repository licence. It's common to put this sort of content under a more permissive licence. Again, it's best (but not strictly required) if this sort of content is grouped together.

A common practice (which has been adopted by REUSE.software) is to capture the full text of other licences in files (named using the licence's SPDX code) under a LICENSES directory in the repository root.

The project should treat contributions under licences that do not match the content as exceptional. Code should be contributed under the project licence, documentation should be contributed under the project's documentation licence, etc. Mixing licences can be challenging, so in an exceptional case where content must be accepted under a different licence, the Eclipse project team should contact the EMO IP Team for support and advice.

/cc @rahulmohang