What are animatable ragdolls using Jolt Physics?

What does this mean?

Animated ragdolls:
Hard keying (kinematic only rigid bodies).
Soft keying (setting velocities on dynamic rigid bodies).
Driving constraint motors to an animated pose.
Mapping a high detail (animation) skeleton onto a low detail (ragdoll) skeleton
and vice versa.

Source - GitHub - jrouwe/JoltPhysics: A multi core friendly rigid body physics and collision detection library. Written in C++. Suitable for games and VR applications. Used by Horizon Forbidden West.