GmsCore
Free implementation of Play Services
...The linux-based open-source mobile operating system Android is not only the most popular mobile operating system in the world, it’s also on the way to becoming a proprietary operating system. How is that? While the core operating system is still released as part of the Android Open Source Project, the majority of core apps are not. It gets worse: More and more libraries and APIs are only available on phones that run various Google apps pre-installed, effectively locking third-party apps to the Google ecosystem. For these reasons Android is described as being a “look but don’t touch” kind of open. ...