Presume that you are flying a fixed path with flight idle thrust way above minium drag speed?
The stronger headwind puts you below the ideal flight path and by reducing the airspeed and changing the position on the L/D curve will allow the aircraft to continue the ideal descent path.
(with fuel savings at the expense of time).
No doubt someone else can explain it with clearer terms as I am from the generation of barber pole descents, with PPL application when necessary, split arse visual circuits and fully established by 400ft.
(PPL - poor planning lever- air brakes) Although my first kite had airborne engine reverse.