The response-header fields allow the server to pass additional information about the response which cannot be placed in the Status- Line. These header fields give information about the server and about further access to the resource identified by the Request-URI.
response-header = Age ; Section 14.6 | Location ; Section 14.30 | Proxy-Authenticate ; Section 14.33 | Public ; Section 14.35 | Retry-After ; Section 14.38 | Server ; Section 14.39 | Vary ; Section 14.43 | Warning ; Section 14.45 | WWW-Authenticate ; Section 14.46
Response-header field names can be extended reliably only in combination with a change in the protocol version. However, new or experimental header fields MAY be given the semantics of response- header fields if all parties in the communication recognize them to be response-header fields. Unrecognized header fields are treated as entity-header fields.