After releasing the Android L preview SDK and system images for Nexus 5 and Nexus 7 (2013, Wi-Fi) devices, Google has posted the partial source code of this upcoming Android version in Android open-source project (AOSP).
The shared source-code includes supported files for Nexus 5, 4, 7 (all versions), and 10. There are still a lot of key components missing, so don’t expect any source-built custom ROMs anytime soon but it is nice of Google to give developers as much of L preview as possible, so that they are ready for the final release later this year.
The release of Android L supported files for Nexus 4 and 7 (2012) and Nexus 10 also indicates that these devices will most likely get Android L update later this year unless of-course Google finds some issue that can’t be resolved.