This add-on saves my eyes big time while I'm doing homework. On top of this, the add-on won't make most websites look like they have been modified in any way (unlike some other add-ons which invert random images and leave blocky artifacts on webpages.) Big thanks to the creator!
Worked pretty much as advertised, but it calls out to Github. IMO, there's no reason for any extension to be calling home unless I allow it, and there's no option to stop this behavior so I'm removing this extension.