[RFC 9110 HTTP Semantics] obsolates previous many scattered specs like 7230, 7231, 7232, 7233, 7235, 7538, 7615, 7694, etc in one consistant http-semantics rfc. It may be useful if 9110 is referred instead of many of those. [RFC 9110 HTTP Semantics]: https://httpwg.org/specs/rfc9110.html