RE: document node attributes

I think it is impossible for a media type to dictate what a server has to serve.  It can
only describe its own semantics.

So there could be a media type -

'application/fooxml'

that required that for
every URL containing a document of its media type,

http://abc.xyz/foo/bar/123

there MUST be a corresponding document containing its links
at

http://abc.xyz/foo/bar/123/<http://abc.xyz/foo/bar/123/links>fooxml
and, say, state that the links MUST be published using a particular
XML syntax with particular semantics to state which attributes,
say, are for the actual links.