What is Prefetching?

There are three types of prefetching:

An example of Link prefetching is when searching with Google. Google search results pages will sometimes tell your browser to prefetch the first result from your search. Even if you decide not to click on that link, your browser still requested that page.

Unfortunately, with the way prefetching is currently implemented in Firefox, it is not possible to selectively block prefetch requests in the same way that other cross-site requests can be blocked. The only option is to disable prefetching completely.