Two weeks after releasing OS X 10.8.3 build 12D68, Apple has seeded build 12D74 to developers. As has been the case with the last few 10.8.3 previews of Mountain Lion, there are no major changes, and no known issues. This one is just taking a while to finally be released to the public for some reason. Apple is asking devs to focus on AirPlay, AirPort, Game Center, graphics drivers, and Safari. Go and grab it is you've got a dev membership!