The Google app provides Android users with tons of functionality, from Google Now to frequent search results from anywhere on the phone simply by swiping up from the home button. Over the years since its release and through its various iterations, Google has continued to improve upon it with many new features and enhancements. Part of this was with the release of the Google Now Launcher, otherwise known as the Google Experience Launcher which integrated Google Now right into the homescreen without having to swipe up from the home button or navigate to the app itself and open it up. The only downside for some people is that the GNL/GEL never had support for auto-rotate on smartphones even though Google implemented it for tablets.
With the most recent update of the Google app which brings users forward to version 5.3, some strings of code were found which look to suggest that Google could be reintroducing the auto rotate function to the Google Launcher. Although it was never part of the functionality in the launcher made available for all users, Google did introduce the auto rotate function briefly in the second developer preview of Android M only to pull it in the third preview which was launched later on in the Summer.
Now it looks like they may be looking to bring it back, although it's unclear whether or not it will be limited to the Google Launcher for those on Marshmallow or be made available to all via the app that already exists on the Play Store. Chances are even if Google makes it compatible with older Android versions, the feature may not go live till Android 6.0 gets released. However, that is expected to be just around the corner so the wait may not be that far out. Also found in this latest apk are some images that appear whenever a user comes up with no search results for apps from inside the app drawer. While this update should be live and already moving out to devices, it may not be live for everyone right away, and if that's the case you can grab the apk file to download and install from here.