Clarification on extensions media type headers

The examples for extensions (e.g. don’t seem to match the requirements in

Specifically they seem to violate:
Content-Type: application/vnd.api+json without any media type parameters.
Accept header MUST specify the media type there at least once without any media type parameters.

Am I missing something?

Sorry for the delayed response.

The text on the extensions page is experimental and non-normative (as it notes at the top). In fact, the extension system is likely to be dramatically overhauled soon.

So, basically, the contradiction you point out means: it’s not compliant to use any media type parameters at the moment, but, were the experimental extension to be adopted, the base spec would be amended to allow the parameters that system needs.

In concrete terms, I’d suggest avoiding the extensions for now because, as I mentioned, they’re likely to change dramatically.