As Nexus 6 smartphone, Nexus 6 tablet, and Nexus Player have now started to ship, Google has pushed Android Lollipop to AOSP (Android Open Source Project), as well as images for Nexus 4, Nexus 5, Nexus 7 (2012 and 2013), and Nexus 10.
You’ll soon be able to retrieve the source code with the following command lines [Update: I still can’t use the lollipop-release branch to retrieve the code, so instead you can use android-5.0.0_r1 tag for Nexus 9, or android-5.0.0_r2 tag for Nexus Player / Android TV]:
repo init -u https://android.googlesource.com/platform/manifest -b android-5.0.0_r1
Currently repo init fails with:
init -u https://android.googlesource.com/platform/manifest -b lollipop-release --repo-url=https://gerrit.googlesource.com/git-repo --repo-branch=stable: revision lollipop-release in manifests not found
But everything should come online soon. In the meantime, you could still browse the code. Anyway that means Android 5.0 images for mini PCs, TV boxes and other devices will hopefully be available in a few weeks, or a couple of months.
Via XDA Developers