The functions http/parse_method, and http/method_to_string treat methods as case-insensitive values by a) converting the method string to lowercase and then matching on it in the former's case, and b) returning lowercase strings in the latter's case

Standard HTTP methods must be sent in upperase, as declared in RFC 9110 — HTTP Standards:

The method token is case-sensitive because it might be used as a gateway to object-based systems with case-sensitive method names. By convention, standardized methods are defined in all-uppercase US-ASCII letters.

This is said to be a "convention", but it surely is enforced by Cloudflare, which controls quite a portion of the internet:

Hence, I believe that these methods should return and accept only uppercase characters for standard methods, instead of converting to lowercase/returning lowercase strings respectively.

Also converting to lowercase in parse_method should definitely not be done, since methods are case-sensitive, and aBCd does not equal abcd.