Google has released a new app in the Play Store, but before you get too excited, it's not technically a new app. It's just new to the store. It's the Android TV Backdrop Daydream app. If you've got an Android TV device, it already has this app installed, but now that it's in the Play Store you should get automatic updates.
The Backdrop Daydream is the app that handles showing you pretty pictures on the screen after your device has been idle for a few minutes. It's also probably the only time a daydream has actually been used on Android. The changelog for this version is just "bug fixes," but Google could add new features to the app over time. Maybe more photo sources or configurable screensaver options? That would be nice, Google.