...
It's most likely USB port power (5V) due to a missing trace on the pcb, so they added that jumper.
Definitely an older version pcb.
That's my educated guess.
Wolfey2014
I think the same, my modules have a slight different layout in that spot
By the way, I'm just desoldering the fans wires (too loud for scrypt mining!) but I would like to found a solution to easily reconnect them if needed...any idea?
I'm thinking to something like a male and female adapter (like that ones
http://img.dxcdn.com/productimages/sku_214072_2.jpg ) connected together and with the fan lines injected as well, but probably the result is pretty bulk...

You could use a male/female inline jack of some sort...prewire the female to your pod and the male to your fan.
You'd end up with a tail hanging out of each ready to plug together if you re-mount the fan and fire it up.
Or you can just leave the fan mounted and unplugged if/until.
It's all at your own risk of course

Good luck!
Wolfey2014