At only 3kb when gzipped, it is a lightweight and efficient library. No extras you don't need.
Hammer doesn't require jQuery or other libraries to work. A jQuery plugin is available though.
Hammer supports Tap, DoubleTap, Swipe, Drag, Pinch, and Rotate gestures. Each gesture triggers useful events and eventData.
These examples are only for showing what you could do with Hammer. It's not an component library.