I listen to game sound tracks on youtube - Super Mario World and the like - and very often, certain instruments play only in one ear, some in the other, which can be jarring. Thankfully, this extension exists. Now I can blast music in my ears all night long while cramming for my exams, and it sounds just the way it used to when I played the games on my old mono TV. The gain slider also helps me find that sweet spot where the sound is just perfect. Dear lovely dev, you just made my life SO much better. Thank you so much! <3
(found this extension as one of the top google search results on a reddit post)