I use Firefox for lots of things but mostly for watching Youtube, and the volume for ANYTHING, not just YT but any site that has sound, is always too low compared to literally any other program on my computer. I always have to turn FF up to max in my sound mixer and all other things down to 25% or lower, just so I can hear YT videos well without other programs blasting my ears off.
All I needed was something to INCREASE VOLUME for anything played in this browser.

So I installed this. I then spent like 20 minutes playing a video clip over & over in both FF & chrome, updating FF, refreshing tabs, closing & reopening FF, and checking the extentions settings for up-to-eleven repeatedly trying to see if it was working or not. Finally I discovered how to manually create the button to toggle the extension on/off (click on the puzzle-piece button in the menu bar, right-click on up-to-eleven when it appears in the drop down menu, and select "pin on toolbar"). Sadly that's the ONLY setting that this extension seems to have; on or off. No volume setting or anything else.

Once I did that, I was able to play a video and click that button to turn the extension on & off while the video played. And guess what? IT DOESNT REALLY INCREASE THE VOLUME. I mean it did get a LITTLE BIT louder, not nearly enough, but mostly it just changed how the sound... sounded. It changed the audio quality, the frequency, the balance, the hertz, or whatever... IDK the technicals of this stuff, I just know that the video I was testing sounded a lot WORSE when the extension was on.

trash

Doesn't seem to do anything.