An update to the OS X 10.8 Mountain Lion Developer Preview 4 was released yesterday afternoon, and the Twittersphere was immediately filled with missives about the features people were finding. A tweet by @Lhunar pointed out a new "Mountain Lion Security Updates" system.
The system apparently does daily checks looking for security updates, downloading and installing them automatically or upon restarting your Mac. This shows Apple's growing concern about malware attacks on the Mac platform, particularly after the Flashback attack earlier this year. The system also includes a more secure connection to Apple's update servers.
For developers who have downloaded and installed Mountain Lion Developer Preview 4, the update is a 1.16 GB download. Apple requests that those developers "[i]nstall this update as soon as possible."
Mountain Lion will be available next month via the Mac App Store for US$19.99.