This is a Schaeffer System roller furling
for a wire luff sail. The wire wire luff of the sail does not replace the headstay; however the system runs parallel to the headstay with the prongs on the portion in the left of the photo
(oriented in the opposite direction of the photo) riding on the stay. This has an advantage of being easily dropped to the deck
and another jib
hanked on, but the disadvantage of not easily keeping as tight a leading edge for close to windward. I've had this same rig on my current
boat for the last 28 years and it suits me well.