2021-08-19 2022-06-21 Expert Review Mark Nottingham hit Boolean When true, indicates that the request was satisfied by the cache; that is, it was not forwarded, and the response was obtained from the cache. fwd Token When present, indicates that the request went forward towards the origin; its value indicates why. fwd-status Integer Indicates which status code (see , Section 15) the next-hop server returned in response to the forwarded request. ttl Integer Indicates the response’s remaining freshness lifetime (see , Section 4.2.1) as calculated by the cache, as an integer number of seconds, measured as closely as possible to when the response header section is sent by the cache. stored Boolean Indicates whether the cache stored the response (see , Section 3); a true value indicates that it did. collapsed Boolean Indicates whether this request was collapsed together with one or more other forward requests (see , Section 4); If true, the response was successfully reused; if not, a new request had to be made. key String Conveys a representation of the cache key (see , Section 2) used for the response. detail String or Token Allows implementations to convey additional information not captured in other parameters, such as implementation-specific states or other caching-related metrics.