Google has asked webmasters and developers that have already deployed App Indexing on their Android apps to join a beta testing program to test out and preview new features they are working on.
Google’s John Mueller posted this on Google+ saying, “we’re looking for some more people to try out things around App-Indexing.” “If you have an app that’s set up for App-Indexing, and want to try things out, we’d love to hear from you,” John added. If you want to participate in this, you can fill out the Google form over here.
To participate, you will have to sign an NDA (non disclosure agreement) forbidding you from discussing the new features you are testing with anyone. But it may be a good chance for you to give Google your two cents on App Indexing and be one of the first to gain those new features.
Google is pushing App Indexing in the mobile search results now promoting Android apps in Google search on Android devices for even apps not installed on the device as part of the mobile friendly Google update.