Wing Chun is a traditional chinese martial art. It was thought to have been started by a woman using speed and structure vs. power and strength. Although there are some other stories that contradict its initial presence, there is not many contradictions about it's effectiveness within close range.
Wing Chun is a martial art that is highly effective on the inside. This range is slightly closer than a typical boxer stands to their opponent but slightly further away than grappling. Wing chun depends on sensitivity of energy and touch. Being able to feel what energy your opponent is giving you and making a choice to go with their energy or redirect it. You will hear good wing chun practioners say "I am being a good listener to what energy is being given to me. " They are not actually listening with their ears... but using their arms and body to feel the energy that is given to them. This is the similiar sort of sensing the energy that wrestlers get from grappling.
There are various principles of wing chun that exist in Jeet Kune Do. The structure is deeply rooted in Jeet Kune do. The centerline principle from Wing Chun is in Jeet Kune Do. Wing Chun was Bruce Lee's initial formal training in martial arts. Hence Jeet Kune Do has a foundation that came from Wing Chun.