Android 6, also known as Android Marshmallow, is the sixth major version of the Android operating system, released by Google in October 2015. It introduced several new features, including improved app permissions, allowing users to grant or deny specific permissions to apps, enhancing privacy and security. Another significant addition in Android 6 is the Doze mode, which helps conserve battery life by putting apps into a sleep state when the device is not in use. This version also improved the user interface and introduced features like Google Now on Tap, which provides contextual information based on what is displayed on the screen.