Newsflash. There are two buttons down there (power and reset). Same buttons / functions as the ones on your cases. Bench testing, etc. Gigabyte feature.
The clear CMOS is the jumper pins just like other Gigabyte boards. Just unfortunate placement of the silkscreen.
Make sense?
The CLR CMOS is on the current GIGABYTE GA-EP45T-EXTREME LGA 775 board. And seeing that the "X58" board shown here looks exactly like the GA-EP45T........
http://www.newegg.com/Product/ShowI...-EP45T-EXTREME ATX Intel Motherboard - Retail