Though it will formally debut later this year in Mountain Lion, Apple has secretly included its new Gatekeeper feature in OS X 10.7.3 Lion, and developers can enable it now to test it.



From AppleInsider:

Apple revealed to developers on Thursday that Gatekeeper is available but disabled in OS X 10.7.3. It informs them that it can be turned on by using the new OS X system policy control command-line tool "spctl(8)".

The command-line tool can be enabled with the command "sudo spctl -- enable" and to turn it off, a developer can simply type "sudo spctl --disable".

  Gatekeeper is hidden in OS X 10.7.3 Lion, developers can preview it now