In five days, OS X 10.8.3 will become the longest beat in the history of OS X. Today, Apple has seeded yet another build, 12D78, to developers for testing. 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. Obviously, something must be up, though, because it's taking forever for this one to hit the public. The two builds before this one were 12D74 and 12D76, so the changes between versions have slowed substantially. 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!