@suanLoBeach No, the mentioned asset likely requires Unity's avatar system for placing feet, hands and so on. Spine does not use any of this, also it's working in two dimensions, not three, so I don't know how that should be transferrable. What would you want to use it for?
If you think you need it for IK foot placement, you can simply use the
SkeletonUtilityGroundConstraint
component that comes with the spine-unity package. Take a look at the Spine Examples/Other Examples/SkeletonUtility GroundConstraint
example scene to see it in action.