UPDATE: Still Available.
https://www.facebook.com/marketplace/107384699291109
(11/25/2020) “1950 Willys Jeep all original, all metal, almost no rust. Runs and drives just like in 1950. Painted to look like an Army Jeep. Lots of extra parts. Needs a little TLC. $10,000 or best offer”
Just a guess, but appears to be a cable-operated overdrive.
I think it might be a throttle cable. I seem to remember some serious off roaders using them so their feet could stay on the clutch and brake pedals.
Both good thoughts. I don’t see an overdrive nor a governor and I can’t see the carb well enough to spot a secondary cable. I suppose this will remain a mystery.
Taking a closer look, i’m inclined to agree with Mark. That cable has a handle that pivots while pulling or releasing the cable similar to what is on some lawn mowers whereas a cable operated overdrive would be a straight pull/push.
I would say hand throttle, like Mark said, I had a buddy who did that to keep a constant throttle when wheeling.
I’d agree with the throttle idea. My son put one of those on his CJ5 shift post for hill starts.