This is ApkOnline, a free android online emulator from where any user can run the APK of an app using only the web browser. Among the different existing user interface configurations, this web extension runs a tablet over Android 6.0 Marshmallow.
ApkOnline can simulate features such as device rotation, some hardware sensors and access to the phone buttons via a menu on the right side of the emulator.
ApkOnline is also integrated with a file manager that can be used to upload and run android APKs. It means that you can use this web extension to test applications without having access to a real android hardware.