What is this light for?

[guenzak]

I am a happy new owner of a 98 Boxster but I am also one of the unfortunate owners that did not get an owners manual with his used car. I have a question on the headlight switch. When the lights are on you can pull the switch out one click which turns on your foglights and a yellow indicator light goes on. You can then pull it out one more click and a green indicator light goes on just below the yellow light but I cannot tell what that does. As far as I can tell no other lights go on. Can anyone outh there educate me on this switch.

Thanks