Datasetdescription MIME type matters

[coret]

When requesting the URL https://research.annefrank.org/media/Beschrijving_uitgebreid_met_RDF.jsonld the server responds (among other) with the header Content-Type: application/octet-stream. The Dataset Register cannot find any datasets as (I assume) Comunica doesn't recognize the content. When providing the same file on a webserver configured to provide Content-Type: application/ld+json for jsonld files, the Dataset can be validated.

You could argue that the .jsonld part of the URL provides information which is more detailed than the more generic application/octet-stream so why not use that signal? Could the our code assist in the recognition part, or is this purely Comunica which makes the determination?

Our API responds in these cases with 406 | The URL can be resolved but it contains no datasets.. A message stating the URL doesn't contain RDF would have made more sense to the user. Can our code make that differentiation?

The Dataset requirements do not make the Content-Type requirement explicit (there's only a comment in regard to the MIME type of distributions). If the Dataset Register / Comunica relies on the Content-Type solely to determine the RDF type, we should make it more explicit. Additionally, we might add a question to the FAQ (what datasetdescription content-types are recognized? link to https://www.iana.org/assignments/media-types/media-types.xhtml).