> Ah, looks like it was somewhat superseded by RFC 4918, but we’re not going to tell you which parts! How about those extension RFCs? There’s only 7 of them…

This is a major complaint I have with RFCs.

If you want to know the current standard for a protocol or format you often have to look at multiple RFCs. Some of them partially replace parts of a previous RFC, but it isn't entirely clear which parts. And the old RFCs don't link to the new ones.

There are no less than 11 RFCs for HTTP (including versions 2 and 3)

I really wish IETF published living standards that combined all relevant RFCs together in a single source of truth.