Android 4.1 Jelly Bean
AOSP technical lead Jean-Baptiste Queru claims that the name of the tagged release is android-4.1.1_r1. Google

Ever since Google's I/O conference took the wraps off the company's Android 4.1 Jelly Bean operating system, the successor to the existing Ice Cream Sandwich (Android 4.0), last month, many developers have reportedly been waiting to try their hands on the latest version of the mobile OS. If you are one of those, then it's time to start your engine as Google has released the Android 4.1 source code to let developers dabble with the mobile OS.

Google's Jean-Baptiste Queru announced Monday that the Android 4.1 source code had been released in the Android Open Source Project (AOSP) under the name android-4.1.1_r1 for everyone to download, examine, and likely attempt to port a whole host of devices, The Verge reported.

We're releasing Android 4.1 in AOSP today. The name of the tagged release is android-4.1.1_r1, JBQ wrote in the Android Building Group. 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.

JBQ mentioned in his note that Google also released proprietary binaries for the newly launched Nexus 7 tablet and the recently banned Galaxy Nexus while the Nexus S and Xoom devices would join the party soon. Although that doesn't mean that full ROMs for all these devices are official, it's a good indication that they will be out sooner than later, according to The Verge.

As noted by Android Community, the .1 in android-4.1.1_r1 most likely refers to a few last minute bug fixes or changes. The full Jelly Bean source code can be downloaded, once it's done uploading and replicating. Developers can begin downloading here.

Meanwhile, the developers' team over at CyanogenMod has already started working on the new Android version. Last week, it was reported that the team took stock of everything that Google announced at the I/O conference in June and is all set to go ahead with the next version, CyanogenMod 10, which would be based on Android 4.1.

At that point of time, the team of CM developers didn't see the source code and hoped that it would be simple enough to work with. And now, with the source code being released, it would be interesting to see how android-4.1.1_r1 coincides with their earlier expectations.