Calrification on ekf aid mask

I am getting confused between frames used in ROS and used by FCU for vision Velocity Fusion.
I am using ROS to publish vision velocity.

    EV_VEL in ROS framework is FLU or FRD ?
    Flight Controller is in FRD so velocity vision should also be FRD ?

  2. What is use of ROTATE_EV ? Does it convert Body frame to NED frame or NED to BODY frame ?