What does this switch do?

[Meir]

first, welcome.
nice set of wheels you got there.
the switch you are showing on the picture is not OEM.
in other words this is an aftermarket switch installed there by the previous owner.
1.do you have an iPod/iPhone cable in the car (connected to the OEM system)?
2. do you have an after market stereo system?
3. do you have ant type of radar detector that came with the car?

if you don't have none of the above, it mast be a self distract button.
don't press it at 4000 RPM just kidding.