Google developers have finally released the source code of the latest version of Android.
Jean-Baptiste Queru said in a note:
We’re releasing Android 4.1 in AOSP today. The name of the tagged release is android-4.1.1_r1. The name of the development branch is jb-dev. We recommend that you create new clients, even if you’re working in the master branch. It’ll make your clients smaller and faster to sync. Proprietary binaries are available for Nexus 7 and Galaxy Nexus. Nexus S and Xoom will follow.