This article is not very information rich, but one thing is clear: this is not a github leak, the code was just posted to github by whoever got access to it. So the headline is pretty misleading.
If the source was not already on GitHub, then a "GitHub Leak" of that source could not possibly be caused by a software error.
Regardless, many of us agree that the title suggests GitHub as a central role to the leak. If, as other commenters say, it was just used as a file host.. it doesn't belong in the title imo. It's just there to pull in more views. It may as well been Piratebay.