Basic idea would be to create a list of bones, and assign a x,y pixel for every frame for every bone.
This would be super helpful for games who want to attach a turret to a tank or get the precise pixel for a projectile to spawn, or properly place the muzzle flash. It could be as simple as to render a frame, and have all the bone x,y values present to properly place additional sprites on it. That doesnt need to be too complex like rotate a bone, and auto rotate others. Simply a list of bone names, and you can place every bone by hand in every frame.