> Link prefetching is when a webpage hints to the browser that certain pages are likely to be visited, so the browser downloads them immediately so they can be displayed immediately when the user requests it. This preference controls whether link prefetching is enabled.
> Possible values and their effects
> true
> Enable link prefetching. (Default)
You can check the value in your Firefox with about:config and searching for network.prefetch-next
My one is "false" and it's shown in bold face, meaning that I changed it to that value. Privacy concerns and also legal concerns: what if a site links another site that the legislation of your country (or the country you're travelling to) doesn't allow you to access? At least I get some hints of where I'm heading to if I'm loading pages myself.
Because Chrome, by default, enables prefetching [0] (it loads links before you decide to click on them). Firefox will never do that due to obvious privacy concerns.
It's the usual "principle vs convenience" thing, where most people choose the latter.
[0] https://support.google.com/chrome/answer/1385029?hl=en