Just a simple skin, basic retexturing of the original biker jacket, available by completing a certain mission with Gerry McReary (I Need Your Clothes, Your Boots, and Your Motorcycle)
I'm sure you can buy it somewhere too.
Installing the *.wdr file (the bump mapping) will affect all alternate clothes from the same type. It is not necessary to use it. You can install only the *.wtd file (texture) if you like.