It aims at increasing the discoverability of useful forks of open-source projects.
Simply type a repository's URL in the Text Field above. Both of those examples are valid entries:
payne911/PieMenu and https://github.com/payne911/PieMenu.

The criteria is simple: if a fork was created, but never received any other activity on its master branch, it is filtered out.
The results are sorted by the amount of stars.