It's a little settings file that determines how your display..displays things.
thanks for istat pro thats super cool!make sure you calibrate your battery first. Also some people like to use smc fan control to be able to control there fan speeds, i found no need for it but you may like it. Coconut battery is also another good program for info about your battery. and you could also download istat pro which is a widget for dashboard found on apples site, it monitors everything about your computer and is a good little app to have. Enjoy your new mac