Investigate content negotiation for protected resources
From version 4.7 on, the VLO has an integrated link checker (from the Curation Module) that checks if a linked resource is fetchable and if not assumes it's protected and displays a lock icon (see https://beta-vlo.clarin.eu/help#accessing-resources). This fails for our (and probably all DSpace) corpora, because instead of a 403 the link checker gets sent to the shibboleth login/ the discovery service. It should be investigated if this is something that might be able to be fixed on the repository side or if the link checker should become more intellig