After the official release announcement of Android 5.0 Lollipop (for now only for Nexus), the source code of the operating system comes to the Android Open Source Project. This is the starting point for custom ROM developers to start building on the new version of the OS, not just Material Design.
With a Lollipop-sized update, it will take some time before the features that Google always integrates into its operating system and doesn't announce, letting independent developers or Nexus users discover the surprises.
For Android developers and advanced connoisseurs, here is the Android Git Repositories link to the OS source code.
(tagsToTranslate) android 5.0 lollipop (t) source code (t) source code (t) so