Apple has released a potential Golden Master (GM) build of OS X Mavericks Server to developers ahead of next Tuesday's media event where the release date of OS X Mavericks is expected to be announced.
Apple has this to say about OS X Mavericks Server on the marketing page for the software:
OS X Server includes a number of innovations that will help the people who use your network as well as the people who manage it. The new features in Xcode Server make it easier than ever for a Mac or iOS development team to create robust, reliable software, thanks to continuous integration, testing, and repository hosting services. Caching Server 2 speeds up the download and delivery of software through the App Store, Mac App Store, and iTunes Store, and it can now cache on your server for faster downloading to iOS 7 devices. And Profile Manager has an array of new management features for iOS 7 and OS X Mavericks that simplify software distribution of apps and books.
9to5Mac says the GM of OS X Mavericks Server comes with a build number of 13S440. It's available from the OS X Developer page. The consumer version of OS X Mavericks reached Golden Master earlier this month.