It is referring to the type of differential that was installed in your axle from the factory. There were two different type of differentials that were installed. One, which is by far the most common, is the Traction-Lok. This is a clutch style limited slip unit. They are an inexpensive, and fairly reliable unit for daily driving, and with carbon clutch discs, seem to be an ok choice for straight line racing. It WILL fail if you have anything close to my level of grip, and you attempt to go throttle in during a corner (the inside tire has more grip than the clutches in the differential, causing them to burn out within seconds), which is why those of us who live to turn the steering wheel use one of the various offerings from Torsen (even though they are triple the cost of a Trac-Lok). Just do not attempt to use a Torsen for straight line launching, because it will break (and in such a serious manner as to require a tow truck to get home) due to the very design that makes it amazing for road racing.
Your car likely has a Trac-Lok equipped. The Torsen cars are relatively uncommon, especially in 2011. One way to check is Torsen cars will have a subtle growl when going through tight, low speed turns, such as into a parking space. The OEM Torsens make less noise than the high end model like my T2R. A Trac-Lok car will not growl in tight corners (unless it is VERY badly broken).
2014 Mustang V6-Built to run TTB, CAM-C, and ESP
Proving to my fellow racers that the disdain that some GT drivers have for V6 drivers is unfounded, one results archive at a time since 2013.