Apple today seeded build 12D54 of OS X Mountain Lion 10.8.3 to developers, marking the sixth beta iteration of the newest version of Mountain Lion. 10.8.3 was first seeded to developers in November.
Build 12D54 comes just eight days after build 12D50, and like the previous build, contains no known issues or features. Build 12D50 brought only minor changes, and asked developers to focus on testing AirPlay, AirPort, Game Center, Graphics Drivers, and Safari.
This post originally referred to Build 12D54 as the seventh developer seed of OS X 10.8.3 when it was actually the sixth seed.