### What needs to get done ## Situation The `license` key complies with SPDX, but the [field's docs](https://github.com/canonical/craft-application/blob/main/craft_application/models/constraints.py#L225) don't state that the value is a license _expression_, nor the constraints. Users might understand it to be a plain a string. ## Request In the `license` docstring: - Mention that it's a compliant SPDX expression. - Indicate that `AND` and `OR` are supported. - Provide richer examples of the expression syntax. - Link to the [full SPDX spec](https://spdx.github.io/spdx-spec/v2.3/SPDX-license-expressions). ### Why it needs to get done The constraints of the key aren't clear in the existing docs.