I may be wrong, but these add-ons seem shady to me. The website pointed to as the homepage is an add-ridden site that is supposedly a community for open-source development, but all the links to 'fork me on GitHub' don't go anywhere. I can't find the source at all. This topic comes up often but these have never been posted and the add-ons have relatively few users (4k, 1.5k, 2k and 0.7k).

I don't know anything about browser add-ons. Perhaps someone who does could take a look and see what's up?