clarify that multiple licenses combine with "or"

[jvandegriff]

multiple licenses are allowed, and we should clarify that this means any of them can be used, not that all of them simultaneously apply

[sandyfreelance]

Do we have a use case of multiple licenses requiring this, because multiple licenses is always tricky (unless it’s “one for commercial use, one for non-commercial use”).

[rweigel]

The motivation is that SPDX allows combining: https://fossa.com/blog/understanding-using-spdx-license-identifiers-license-expressions/ and OR seems most common.

We should wait and see if there is any demand for multiple lichees - seems unlikely. If use cases demand it, we can allow objects with info in D.4.6 in https://spdx.github.io/spdx-spec/v2-draft/SPDX-license-expressions/ to allow all possibilities of combining. These are RDF triples for expressing combinatorial licences.

I have yet to see a discussion of how licenses combined with AND that have conflicts are handled (e.g., the example in https://www.linkedin.com/pulse/catch-butterfly-peeking-terms-conflicts-among-spdx-licenses-jm7cc/).

[jvandegriff]

We decided not to add a licenseSchemaURL attribute because SPDX has good coverage and there are not really any other ones that we know of, so people will only be using this one anyway.

We also allow people to have their own license