Orchestrator-workers on Where ten HTTP header fields are defined

All ten fields are currently defined by RFC 9110, RFC 9111, RFC 6797 or RFC 8288. One check is unfinished: no worker could open a status page confirming that none of these four RFCs has itself been obsoleted.

Caching fields: RFC 9111, "HTTP Caching" (https://www.rfc-editor.org/rfc/rfc9111.html)

• Age: Section 5.1
• Cache-Control: Section 5.2
• Expires: Section 5.3
• The page header says "Obsoletes: 7234", so the older RFC 7234 definitions don't count.

Semantics fields: RFC 9110, "HTTP Semantics" (https://www.rfc-editor.org/rfc/rfc9110.html)

• Last-Modified: Section 8.8.2
• ETag: Section 8.8.3
• Location: Section 10.2.2
• Retry-After: Section 10.2.3
• Vary: Section 12.5.5
• Its header lists "Obsoletes: 2818, 7230, 7231, 7232, 7233, 7235, 7538, 7615, 7694". That replaces the older definitions in RFC 7231 and RFC 7232.

Strict-Transport-Security: RFC 6797, Section 6.1 (https://www.rfc-editor.org/rfc/rfc6797.html)

• Section 6.1 gives the definition and the syntax rules (ABNF).
• Section 15 only registers the field with IANA, so it is not the defining section.

Link: RFC 8288, Section 3 (https://www.rfc-editor.org/rfc/rfc8288.html)

• Section 3 opens with the definition and the rule Link = #link-value.
• The page header says "Obsoletes: 5988", so RFC 5988 doesn't count.

Limits of the evidence

• RFC status not confirmed. Every status page the workers tried either returned 404 or redirected to the RFC text itself. That covers rfc-editor.org/info/…, the datatracker pages and the IANA field registry.

  • The RFC pages they opened showed no "Obsoleted by" line.
  • A search for anything replacing RFC 9110 found nothing.
  • So the evidence that these four RFCs are still current is indirect.
• Line breaks in quotes. Several quoted sentences ran over more than one line on the fetched pages. The workers joined those lines with single spaces, so a strict check on whitespace could flag them.
• No sources disagreed.

{"answers":[{"field":"Age","rfc":"9111","section":"5.1","quote":"The \"Age\" response header field conveys the sender's estimate of the time since the response was generated or successfully validated at the origin server.","url":"https://www.rfc-editor.org/rfc/rfc9111.html"},{"field":"Cache-Control","rfc":"9111","section":"5.2","quote":"The \"Cache-Control\" header field is used to list directives for caches along the request/response chain.","url":"https://www.rfc-editor.org/rfc/rfc9111.html"},{"field":"Expires","rfc":"9111","section":"5.3","quote":"The \"Expires\" response header field gives the date/time after which the response is considered stale.","url":"https://www.rfc-editor.org/rfc/rfc9111.html"},{"field":"Last-Modified","rfc":"9110","section":"8.8.2","quote":"The \"Last-Modified\" header field in a response provides a timestamp indicating the date and time at which the origin server believes the selected representation was last modified, as determined at the conclusion of handling the request.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},{"field":"ETag","rfc":"9110","section":"8.8.3","quote":"The \"ETag\" field in a response provides the current entity tag for the selected representation, as determined at the conclusion of handling the request.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},{"field":"Location","rfc":"9110","section":"10.2.2","quote":"The \"Location\" header field is used in some responses to refer to a specific resource in relation to the response.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},{"field":"Retry-After","rfc":"9110","section":"10.2.3","quote":"Servers send the \"Retry-After\" header field to indicate how long the user agent ought to wait before making a follow-up request.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},{"field":"Vary","rfc":"9110","section":"12.5.5","quote":"The \"Vary\" header field in a response describes what parts of a request message, aside from the method and target URI, might have influenced the origin server's process for selecting the content of this response.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},{"field":"Strict-Transport-Security","rfc":"6797","section":"6.1","quote":"The Strict-Transport-Security HTTP response header field (STS header field) indicates to a UA that it MUST enforce the HSTS Policy in regards to the host emitting the response message containing this header field.","url":"https://www.rfc-editor.org/rfc/rfc6797.html"},{"field":"Link","rfc":"8288","section":"3","quote":"The Link header field provides a means for serialising one or more links into HTTP headers.","url":"https://www.rfc-editor.org/rfc/rfc8288.html"}]}