Interpreting JSON as JSON-LD / Content-Type header spec. requirements

Hi list,

In am writing tests and possibly a
​n
 async document loader implementation for jsonld-java that could check
Content-Type and Link headers before fetching.  The current one does not.

I would like
​to ​
research and find actual examples where the JSON-LD specification about the
Interpretation requirement has been observed.  Anyone know a site that serve
​s​
Content-Type application/json with a Link header that provides a "
http://www.w3.org/ns/json-ld#context" relation?

Also could some
​one
 please explain why application/ld+json is forbidden to provide an #context
relation with a Link Header?  Is an #context relation (if served as
application/ld+json) allowed to specify a  http://www.w3.org/ns/json-ld
profile?  Or could a non http://www.w3.org/ns/json-ld Content-Type profile
be served as application/json and provide a secondary #context relation if
it were itself an #context ?  Should the document loader check (and
​subsequently
 dereference the relations) if "second-step" remote documents provide Link
and/or Content-Type profile?  Should there be a processing "order of
precedence"?

Just trying to understand required hypermedia options and possible use
cases.

Thanks,
Christopher Johnson
Scientific Associate
Universitätsbibliothek Leipzig

[1] https://stackoverflow.com/questions/39551829/usage-for-
profile-parameter-for-json-ld-requests
[2] https://json-ld.org/spec/latest/json-ld/#interpreting-json-as-json-ld
[3] https://github.com/IIIF/api/issues/1066
​[4] https://github.com/ProfileNegotiation/I-D-Accept--Schema​