Android 4.3 brings OpenGL ES 3.0, Bluetooth Smart, restricted profiles, new media capabilities, notification access, and improved profiling tools.
Google finally exposing OpenGL ES 3.0 APIs is great as Android developers can now leverage this mobile graphics API that's a huge update over GLES 2.0. OpenGL ES 3.0 was released last year and incorporates various elements of desktop OpenGL 3/4.
Bluetooth Smart support is for Android communication support with Bluetooth Smart devices. Restricted profiles is for limiting device hardware/software access whether it be for a Android kiosk or family/children protection. The new media capabilities come in the form of a modular DRM framework so developers can more easily integrate DRM into their own streaming protocols.
More details on Google's Android 4.3 Jelly Bean update can be found from their blog announcement.