FaceFX Documentation and support
Bone curves are curves with the same name as a bone in the rest pose. They control the amount that the bone will be controlled by FaceFX in the current animation.
Note: bone weights are simply passed back from FaceFX to the game engine. It is the game engine’s responsibility to use that weight during its animation blending step. If bone weights aren’t working in your game, talk to a programmer about supporting FaceFX bone weights.