updated 03:07 pm EDT, Wed August 13, 2014
Focus areas remain same as second release
Apple is now seeding a third beta of OS X 10.9.5 to developers. The software has a 13F14 build number, and focus areas identical to the previous beta. Developers are asked to test Safari, graphics, Thunderbolt support, and USB/USB smart cards.
The v10.9.5 update will likely be the last for OS X Mavericks as Apple prepares to ship Yosemite sometime this fall. It's not clear how many more betas will be issued, but as a purely maintenance release 10.9.5 will likely be finished in or by September.