Get a document from a specific project. Documents with state unpublished will be retrieved.
Only documents that have been previously added to a project will show on the response. Check how to make changes to channels and content in a Project.
A document in core may be have changes that aren't yet published, these are stored in a separate variant of the document (the 'unpublished' variant). When requesting a document for core, the 'published' variant is retrieved, unless there is none (the page has never been published yet), in which case the unpublished variant is fetched.