Apple has just posted a new pre-release developer seed for upcoming OS X Mountain Lion 10.8.4, Build 12E55.
In the notes accompanying the seed release, which includes Combo (comprehensive) and Delta (just changes) update installers, Apple notes the same focus areas as the last few seeds: Wi-Fi, Graphics Drivers, and Safari. This seed, though, also has Windows File Sharing, a new addition to the list since the last seed, build 12E47, which was released at the beginning of this month.
Could this rapid release schedule mean that 10.8.4 is getting closer to actual release to consumers? As this is the sixth developer release of 10.8.4, and 10.8.3 went through 13 different seeds, the answer may be a qualified no, as Apple tends to iterate on its dot releases fairly often and consistently.
Source: Apple Developer Center.