Apple has seeded OS X 10.8.3 build 12D65 to developers just a week after releasing the 12D61 build. Apple is asking developers to focus on AirPlay, AirPort, Game Center, graphics drivers, and Safari in 12D65. The update also appears to fix the "File:///" bug that currently plagues OS X, where by typing that into a text field, you immediately crash the app you are working in. If you're a Mac dev, you can grab the update through the Mac App Store right now.