March 20, 2020 update:

Build ARCore apps without OpenGL

Sceneform is a 3D framework that makes it easy for you to build ARCore apps without OpenGL.

As of 1.16.0, the Sceneform SDK for Android is open source and available from github.com/google-ar/sceneform-android-sdk

This site (developers.google.com/sceneform) documents the previous version, Sceneform SDK for Android 1.15.0.