Googling found a solution to the error in the manifest:
App is not indexable by Google Search; consider adding intent-filler activity with an ACTION-VIEW. See issue explanation for more details.
Need to add a link to the site:
<action android:name="android.intent.action.VIEW" /> <category android:name="android.intent.category.DEFAULT" /> <category android:name="android.intent.category.BROWSABLE" /> <data android:scheme="http" android:host="www.example.com" android:pathPrefix="/gizmos" /> <data android:scheme="example" android:host="gizmos" /> But one thing is not clear what the prefix means?
android:pathPrefix="/gizmos"