As we broke first (yes, we are the best), Google renamed Google App Indexing to Firebase App Indexing. Truth is, the code base is the same, so you don't need to do anything new for your Apps to be included.
Google did revamp their documentation and move it all to firebase.google.com/docs/app-indexing.
Mariya Moeva from Google explained on Google+:
We've taken your feedback on board and redesigned the App Indexing docs! Check them out in their new home in Firebase:1) case studies featured front and center on the homepage,
2) lots more code samples and codelabs linked from the docs,
3) my new favorite feature: search preview! Enter a web URL or an app URI of an app that uses the API and see the magic.
One of the cool new features as Mariya said is the search preview, you enter the app URL and it takes you to how it looks in the Google smartphone results. For example, here is our app (download if you have not) in the preview.
Google also announced it is moving the app analytics to Firebase analytics, which looks amazing but I wish they'd keep it under Google Analytics.
Here is a video:
There is so much more around this Firebase news, read it all over here.
Forum discussion at Google+ and WebmasterWorld.
