This is a way of marking territory if they are rubbing the sides of their faces on the object. Cats have scent glands around their lips and on their chins. The facial pheromones that they mark with are signals of a happy or calm cat to other cats.
The part that simultaneously enables the axle to flex while transmitting the driving force is called a drive axle joint, and is also known as a constant velocity (or CV) joint. The CV Boot is a ribbed, rubber flexible boot that keeps water and dirt out of the joint and the special grease inside the joint.
The CVT is an automatic transmission that uses two pulleys with a steel belt running between them. To continuously vary its gear ratios, the CVT simultaneously adjusts the diameter of the drive pulley that transmits torque from the engine and the driven pulley that transfers torque to the wheels.