This is really cool. One little detail I've noticed is that it doesn't seem to apply to private repositories, which seems like a bit of an oversight. The repo I'm checking clearly having an Apache 2.0 license text in the LICENSE file. Just because a particular copy of a repo is private doesn't mean that the code within it isn't still bound by an open source license.
EDIT: Before anyone replies with "Why would you want that?", it's fairly common to stage a project privately on GitHub before publicly releasing it. It'd be nice to see that the license is detected correctly before going public with it. As it is now, I don't know what'll happen until I go public, and my first public commit in the repo may well be fixing up something minor to get the license detected properly.
It seems to work fine on my org's private repos. Not sure if it's having trouble detecting the license in your case, or if it just hasn't worked through all the repos yet, or what.
EDIT: Before anyone replies with "Why would you want that?", it's fairly common to stage a project privately on GitHub before publicly releasing it. It'd be nice to see that the license is detected correctly before going public with it. As it is now, I don't know what'll happen until I go public, and my first public commit in the repo may well be fixing up something minor to get the license detected properly.