2008 Honda Civic Question?

I have an 08 lx civic. I know this is probably a dumb question but... On the driver’s side where the door panel is, there are 4 ons. One is for door locks, 2 are for the driver’s side and pengers side windows and there is a fourth one in the top right corner. What does this on do and also at night it is not lit. Is mine bulb or burnt out or is it just not illuminated from the factory?