The slits are for the posts that are used to retain the floor mats. The floor mats have grommets (one per mat on the older models, 2 per mat on the newer) and there are little brackets with a post that are screwed to the floor. The post on the bracket sticks up and the grommet in the floor mat fits over it.

I believe they're all slit for the posts at the factory.

 

Get a good set of Muz Prestiges mats;problem solved.!!!

 

I have the oem posts w. the oem floor mats. The slits are exactly as everyone described right on the brace. I never noticed until the other day either.

I'll snap a pic and post later.



edit: While viewing the forum i found this pic of someone elses ride. You can see the slit on the brace. Mine, however is located in the same spot more toward the center console.

 

I have the same slits too. At first I thought it was caused unintentionally, after review it seems it comes like that direcly from the factory.