Here's an example that's actually stamped in the edge. With some pads the code is inked on the backing plates.

This is a genuine Mopar replacement pad for the 4 piston Kelsey Hayes brakes. Friction rating is FF. If nothing else, this lets you and your mechanic know that anything less, such as EF or EE is probably not going to stop as well as original.

(PS I did not love these pads in case anyone thinks I'm promoting NOS pads as the hot ticket to braking bliss)