RFC lookup

Look up IETF RFCs and read what a specification actually says. Use whenever an RFC number comes up ("RFC 9110", "RFC 2616", "rfc7231"), when checking what a protocol spec requires, when quoting normative MUST/SHOULD/MAY language, when asked "what does the spec say about X", or when verifying whether an RFC is still current or has been obsoleted. Covers HTTP, TCP/IP, DNS, TLS, QUIC, SMTP, OAuth, JSON/JOSE and every other IETF standard. Finds the right RFC, reads one section instead of the whole document, and flags superseded specifications before they get cited.