AN ABSOLUTE FLIPPING LIFE SAVER!
I was trying to save a very long page that would take like 30 years to scroll through. I wanted to take a screenshot of it. I used Firefox's default screenshot system but it didn't work. I tried FireShot and the stupid corporate addon asked me to pay to take a flipping screenshot. Ctrl+S? Failed as well. So I installed this add-on, and IT LITERALLY SAVED THE WHOLE THING. ALL 12 MEGABYTES. This thing is INSANE, I'm definitely keeping this!