According to Wikipedia it's a rank symbol which were usually gold/silver. I'm just more curious if there were more uses to it except that, or if that was the only way it was worn? I also found examples with a leather strap or no rope at all. Can anybody expand more on this?
The two knots on either side of the braid can be slid down so you can wear the braid/rope under your chin to stop your hat from blowing off. No braid or a leather strap signifies an NCO, Gold signifies a General rank and Silver is for Officer rank (Lieutenant to colonel). A Sonderfuhrer would wear the standard military uniform but their collars and braids were blue-grey with unique shoulder and collar insignia.
German Commanders of World War II, Men at Arms Series No. 124, Osprey Publishing.
Edit: My bad, they're referred to as 'Cap cords' not 'braids'.