Gated-execute on Where ten HTTP header fields are defined

All ten fields are defined in RFCs I opened and read. I did not find any sign that these RFCs have been obsoleted. That check was limited: the pages I opened showed no "Obsoleted by" notice, and one search turned up no replacement RFC. RFC 9110 and RFC 9111 are the HTTP specs that replaced RFC 7230–7235 and the older HTTP/1.1 specs, and RFC 8288 itself obsoletes RFC 5988.

• Age, Cache-Control, Expires: RFC 9111 (HTTP Caching), sections 5.1, 5.2 and 5.3.
• Last-Modified, ETag, Location, Retry-After, Vary: RFC 9110 (HTTP Semantics), sections 8.8.2, 8.8.3, 10.2.2, 10.2.3 and 12.5.5.
• Strict-Transport-Security: RFC 6797, section 6.1.
• Link: RFC 8288, section 3.

Sources: https://www.rfc-editor.org/rfc/rfc9111.html, https://www.rfc-editor.org/rfc/rfc9110.html, https://www.rfc-editor.org/rfc/rfc6797.html, https://www.rfc-editor.org/rfc/rfc8288.html

{"answers":[
{"field":"Age","rfc":"9111","section":"5.1","quote":"The Age field value is a non-negative integer, representing time in seconds (see Section 1.2.2).","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":"An origin server SHOULD obtain the Last-Modified value of the representation as close as possible to the time that it generates the Date field value for its response.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},
{"field":"ETag","rfc":"9110","section":"8.8.3","quote":"An entity tag consists of an opaque quoted string, possibly prefixed by a weakness indicator.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},
{"field":"Location","rfc":"9110","section":"10.2.2","quote":"The field value consists of a single URI-reference.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},
{"field":"Retry-After","rfc":"9110","section":"10.2.3","quote":"The Retry-After field value can be either an HTTP-date or a number of seconds to delay after receiving the response.","url":"https://www.rfc-editor.org/rfc/rfc9110.html"},
{"field":"Vary","rfc":"9110","section":"12.5.5","quote":"A proxy MUST NOT generate \"*\" in a Vary field value.","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"}
]}