Found this information:
Early SAU-23 (autopilot) version feed two signals into the yaw channel - damping and stability. The second was feed in by a side slip sensor (DUS-3) right ahead of the cockpit. This was used to wash out side slip in horizontal flight only. It was disengaged at more than 6? roll angle automatically.
The ARI I was talking about was added with later SAU-23A versions. Beside the damping and stability (this time not yaw angle but yaw acceleration) the ARI input was fed into the yaw channel. This third input/signal was formed by pilot's stick motion and angular rate and angular acceleration of all axes (and dependent from wing sweep angle). It was automatically engaged above 24? AoA.
May have been removed on some of the aircraft I am familiar with as the the auto-pilot was not used.