What is the small button in the center botton on the dash cluster?

What is your question?

You have the mileage button you push to set it back to zero on how many miles you have traveled on a tank of gas. But just left and below (centered) is a button. What is it used for?

How long has your 2001 Honda Prelude had this problem?

Months, the brake light stayed on. When I pushed the button it went off. I need to know what the button is for. It's in the Manuals that came with the car but no where in the book does it say what it's used for.