Following yesterday's public release of Safari 8.0.4 for OS X Yosemite, Safari 7.1.4 for OS X Mavericks, and Safari 6.2.4 for OS X Mountain Lion, Apple has seeded Safari 7.1.5 and Safari 6.2.5 to developers for testing purposes. Safari 7.1.5 is for Mavericks users, while Safari 6.2.5 is for Mountain Lion users.The Yosemite equivalent, Safari 8.0.5, is already available to developers and public beta testers as it is built in to OS X 10.10.3.
In the beta notes, Apple asks developers to focus on general website compatibility, extension compatibility, debugging using the Web Inspector, typing in the Smart Search Field using multiple displays, viewing videos on sites like Netflix and YouTube, Address and Password AutoFill, and more.
Apple Seeds New 7.1.5 and 6.2.5 Safari Betas to Developers for Mavericks, Mountain Lion [Mac Blog]