Apple has just provided the very first beta build of OS X Mountain Lion 10.8.1 to developers – the first incremental update to Mountain Lion. Updates like this typically contain mostly bug fixes and stability improvements.
The build number of the beta is 12B12, and the package is available now through the Mac Developer Center as a delta update, weighing in at just 38.54MB. The build lists no known issues, and Apple is asking developers to focus on testing Active Directory, Microsoft Exchange in Mail, PAC Proxies in Safari, SMB, USB, and WiFi and Audio when connected to the Apple Thunderbolt Display.
Earlier this week, 9to5Mac reported that Apple was preparing to seed the update to their AppleSeed program.