Google is working with more developers to get their apps included. Right now, Google Search will work with a group of selected apps. The new features are, as Google says, "rolling out now" on the Google Search app or on the Chrome or Android browsers. As important as information is, adding more sources to Google Search can only make it better. And for developers, it gives them a chance to get their apps in front of Android users who already have displayed an interest in the subject matter pertaining to their app.
Update to Google Search brings information from your installed apps
1. Google Search will find relevant information from your installed apps
2. Search for apps and get a list directly from the Google Play Store
source: Google via AndroidCentral