The Golden Master build number of newly OS X Mavericks GM is 13A603. The last two weeks back build release number was 13A598.
We don't have any sort of changes made by Apple in the Golden Master build, we clearly know this build release was not a planned and probably released fix some bugs that was spotted at last released 13A598.
Developers who are looking for latest Golden Master build can instantly download from Developer Center, its not available in Mac App Store.
Already announced OS X Mavericks in Apple's WWDC 2013 event, Apple is reportedly announce the OS X Mavericks on October 22nd Apple's event.
