Nylon Interface Prevailing Torque Fasteners
WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
These fasteners accomplish the thread interface by the presence of a nylon material on the fastener threads.