As noted by MacRumors, today Apple seeded the fifth beta of Mac OS X 10.6.7 to developers. Build number is 10J858 and, contrary to previous releases, Safari has been added to the focus areas for testing the new version of OS X, which already included Bonjour, Mac App Store, AirPort, SMB and Graphic Drivers. The new build is available now in the OS X Dev Center. No known issues have been listed in the documentation and the update weighs 20MB than the previous download.
Fourth beta of Mac OS X 10.6.7 (10J855) was released on February 11th. Apple has been seeding betas of 10.6.7 since January, and it is still unclear at this point when they’re planning on publicly releasing the update.