Android 6.0, also known as Marshmallow, was released by Google in 2015 and focused on refinement, performance, and user control rather than flashy redesigns. It introduced runtime app permissions, allowing users to grant permissions individually instead of all at install time. The Doze mode significantly improved battery life by reducing background activity when the device is idle. Marshmallow also added Google Now on Tap, native fingerprint authentication, improved app links, and better memory management. Support for USB-C, adoptable storage for SD cards, and enhanced accessibility features made Android 6.0 a stable and practical upgrade for many devices.