Github appears to have disabled access to a number of repositories in response to a DMCA takedown by Whatsapp's general counsel in February 2014. These repositories appear to contain code that allows developers to create apps that can communicate with the official whatsapp client. The biggest target of this takedown is Tarek Galak's Open Whatsapp platform. http://openwhatsapp.org/
Take a look at the takedown notice here - https://github.com/github/dmca/blob/master/2014-02-12-WhatsApp.md
Several of those counternotices were filed at the very end of last month, and the 10 business days have not yet elapsed. Github can't put them back online early unless it wants to lose the liability protection.