Mountain Lion - Developer Preview 4 Build 12A256

Apple released a Security Update for Mountain Lion via the Mac App Store.

This update tests the new Mountain Lion Security Updates system. The new system includes:

•  Daily Checks for required security updates
•  The ability to install required security updates automatically or after restarting your Mac
•  A more secure connection to Apple's update servers.

This update includes general updates and improvements to Mountain Lion Developer Preview 4.

I think the Privacy Settings got updated as well.

Read more about Mountain Lion.