Apple has released an update for the new MacBook Air and MacBook Pro models, including the Retina MacBook Pro, just released this past June. The update fixes several issues:
About MacBook Air and MacBook Pro Update 1.0
This update fixes an issue that can lead to increased CPU power consumption, and it improves compatibility with some USB devices.
This update is recommended for all Mac notebooks introduced since June 2012.
The update weighs in at 76.64MB and is available via Apple's software update webpage or via the Software Update function built into OS X.
Top Rated Comments
Considering it says its for the new MBA and MBP models, thats not at all surprising.
As noted no fewer than 3 times in this thread...
EDIT: Looking further into the pkg, this seems to update Dock.app and various supporting files, frameworks, and bundles.