What's it do? (i.e., what mission/purpose is it intended to perform?)
Replaces the F35B when it gets cancelled in next year's budget.
The demonstrator’s rotors are driven by advanced electric motors powered by rechargeable batteries; future hybrid solutions have also been investigated using a diesel engine to drive a generator. All of the aircraft control systems, flight control and landing gear actuators are electrically powered, removing the need for any hydraulic system.
I hope they're not Li-Ion.