Off topic, but that's a shame about them recommending not to prefix X- for custom headers. Their entire reason (Appendix B) is that "well, if the header eventu

Off topic, but that's a shame about them recommending not to prefix X- for custom headers. Their entire reason (Appendix B) is that "well, if the header eventually becomes a standard header, then there will be old apps that will only work with X-, and we'll have to keep the X- version around forever!" That seems like a very weak reason to me. Most custom headers are not going to become standard headers, and those that do, well, apps can update nowadays and we deprecate old web features all the time. I see a lot of value in distinguishing non-standard headers as a matter of principle. Also, there's a little bit of classic charm to X-, it's almost a shibboleth of HTTP. Removing it feels as wrong to me as removing the :// from the URI protocol and saying "we really just need :/"