Google Play Services takes care of lower-level APIs and background services, and the other part of Google's fragmentation takedown plan involves the Play Store. Google has been on a multi-year mission to decouple just about every non-system app from the OS for easy updating on the Play Store. Take a quick look at Google's Play Store account and you'll see a huge list of apps, many of which ship by default in Android. Gmail, Maps, Search, Chrome, Calendar, the keyboard, YouTube, and even the Play Store itself are all separately updatable.