I'm a little uneasy that the majority of headers that are prefixed with Content- are actually scoped to the selected representation.

E.g., Content-Length, Content-Type, Content-Encoding, Content-Language. The only registered, current Content- headers that actually about the content (using the current definition in Semantics) are Content-Location and Content-Disposition, AFAICT. Not sure about Content-Range; it's defined in terms of the selected representation, but could equally be defined in terms of content, I suspect.

It might help to add a small note to the content section that explains that the Content- prefix doesn't necessarily imply that the header is strictly about the content. Also might be worth mentioning in the registration considerations.