Apple has seeded build 13D61 of OS X 10.9.3 to developers, just a little over a week after releasing the ninth OS X beta, build 13D55. Safari 7.0.4 accompanies the new build.
Apple is continuing to ask developers to focus on Graphics Drivers, Audio, Mail, Contacts and Calendar sync over USB in iTunes, and Safari.
The beta is available for developers via the Update tab in the Mac App Store, and the Mac Developer Center.
OS X 10.9.3 is seems to be nearing public release, as AppleCare employees were today seeded 10.9.3 build 13D62, one build later than what developers are receiving. A public launch could come as soon as this week.