Just got a new 2010 Elantra SE. Just noticed...right next to the driver's visor (just beyond the recess for the visor, by a couple of inches) there's a small plastic rectangle (about 1" x 2") affixed to the ceiling, with grooves on it. It doesn't seem to "do" anything--it's not a switch or a light, etc. Why is it there? What does it do, if anything? The owner's manual makes no reference to it.