The count of contributions (summary of Pull Requests, opened issues and commits) to public repos at GitHub.com from Sat, 17 Nov 2012 22:58:25 GMT till Sun, 17 Nov 2013 22:58:25 GMT.
Only first 1000 GitHub users according to the count of followers are taken. This is because of limitations of GitHub search. Sorting algo in pseudocode:
githubUsers .filter((user) -> user.followers > 30)