A new build of Mac OS X 10.6.7 hit the Developer Center last night, the third one since Apple started seeding 10.6.7 to developers three weeks ago. Build 10J850 mentions, again, Mac App Store, AirPort, Bonjour, SMB and Graphics Drivers as focus areas for developers to test.
The second build of 10.6.7 was released on January 25th, and it appears that Apple is quickly issuing new builds with the same focus areas and no “known issues”.