Undocument feature of BoneTransform

Troubleshooting General Help
1

public void update(int prevFrame, int currentFrame, int interpType,
            float time) {
        if (bone == null) {
            return;
        }
        logger.info(bone.getName());
        if (bone.getName().equals("Bip01-node")) {
            logger.info("BIP 01");
        } else {
            interpolateRotation(rotations[prevFrame], rotations[currentFrame],
                    interpType, time, bone.getLocalRotation());
            interpolateTranslation(translations[prevFrame],
                    translations[currentFrame], interpType, time, bone
                            .getLocalTranslation());
            bone.propogateBoneChange(true);
        }
    }



I'm curious what the BIP 01 is there for? It's an exclusion rule so that no BoneTransforms modify BIP 01, but why?