Turns out this was made by a fan using <a href="https://github.com/IonicaBizau/github-contributions" rel="nofollow">https://github.com/IonicaBizau/github-contributions</a>
thanks to GitHub's ability to accept commits in the past.<p>Another similar tool is: <a href="https://github.com/gelstudios/gitfiti" rel="nofollow">https://github.com/gelstudios/gitfiti</a>