Prefetch / Preload
A browser optimisation that fetches likely-next resources before you actually request them.
Prefetching and preloading warm the cache for links, scripts and images the browser predicts you'll need. It makes navigation feel instant when the guess is right, at the cost of extra data usage and, in some cases, sending requests (and cookies) to sites you never actually visited.
Browsers give users controls to disable it; ad and tracker blockers strip prefetch hints pointing at known tracking domains so predictions don't leak data.