As I understand it, Vimium for Chrome and Vimium-FF share the same code base (https://github.com/philc/vimium), even the addon site for Vimium-FF just calls it "Vimium" (https://addons.mozilla.org/en-US/firefox/addon/vimium-ff/).

So if it's in Firefox, it's Vimium-FF. (And I'm using Firefox, in case that wasn't clear.)