Ive seen PWM 2 pin jumpers on ifirobotics.com (more specifically on this page) and a number of BattleBots stores but I’m not familiar with their purpose. I also know that they are used a bunch in computers (I harvested 9 out of one of the older computers I had). Any insights would be welcomed. 
They’re used to short together two adjacent pins. Normally for different settings, as is their purpose on the Victors.
I know in VEX they also determine if the robot runs automode or driver control.
A place you’ll find one of these jumpers, other than on the Victors, is on the OI. It is used to select between the two possible dashboard readouts (RC or OI).
It is the Brake/Coast jumper on the speed controller. This is the same jumper that can be found in computer hardware like motherboards, disk drives and expansion cards. It is also known as a zero ohm jumper.