Apple has seeded a pre-release of Safari 5.2 to registered developers.
After the release of the OS X Mountain Lion developer preview, a new beta of Safari has been made available with browser features from Apple’s upcoming Mac OS X Mountain Lion.
Named as, Safari 5.2 for OS X Lion introduces the unified, Google Chrome-like address/search bar. There are some other minor cosmetic changes that mirror the Safari version from the Mountain Lion developer preview.
Apple had recently seeded Safari 5.1.4 to developers with bug fixes and minor improvements. 5.2 is the next major update for existing users that will likely not be released until OS X Mountain Lion this summer.
Xcode 4.4 was also released recently to help developers get their apps ready for Mountain Lion.
Source: Cult Of Mac