That's great to hear. One particular example which I found needlessly strict is this: The request MUST contain a Content-Type header whose value is app

That's great to hear. One particular example which I found needlessly strict is this: The request MUST contain a Content-Type header whose value is application/json. It MUST also include application/json as the only or highest quality factor. It makes sense for fully compliant implementation to have those headers, but they way I understand MUST here is that a server would reject any request without them.