Yeah, I know about that. It's unfortunately not as snappy or usable as Chrome's, because you can't activate the search with a single key combination. The item focus behavior is also distracting: when you type in your search, the best match is not automatically focused, so you have to press the down arrow key and then press enter to activate it. In Chrome, you just press Ctrl+Shift+A, type in the search, and press enter (99 % of the time). So for the whole process, Firefox has two extra steps. It ends up being a lot because I use this feature dozens of times in a day.