The Android Game SDK is a new set of libraries for Android game developers intended to streamline development. This post explains how to use it.

File → New → Import project → Select your export folder from above step. In a pop-up asking me if I should use the project SDK or Android SDK I chose to use Android SDK (which is newer than the one of ...

When the Import Unity Package window appears, click the Import button. Download the Google Sign-in Unity SDK (version 1.0.4) from the Google Sign in SDK website.

As Unity 3D is (mostly) not open source, Google must be working directly with the developers of Unity on the Android Game SDK.