Is there any reason that the entries x-dns-prefetch-control and x-ua-compatible should not be removed? They do not meet the requirements for inclusion per the spec. at this stage:
Such extensions must use a name that is identical to an HTTP header registered in the Permanent Message Header Field Registry…
Hixie: If they are implemented by software, the solution is to fix the IANA registry, not this one.
Theimp: When that's done, they can be re-added.
Hixie: That's putting theoretical purity before pragmatic documentation of interoperability.
Theimp: No, it's not. Anyone is as free to propose additions to the IANA Permanent Message Header Field Registry, as they are to edit this wiki. Document it there first, as required by the HTML spec. By all means, please document everything — but follow the standards process and begin at the beginning; not at the end.
Hixie: No. The goal is to document reality. Reality is that these fields are used. It would be ridiculous to remove documentation just because the IANA list is out of sync with reality. If you think IANA should be updated, then by all means, be my guest.