What is under the hood for L4 for Mac?

I know that the Windows version of L4 uses .Net and WPF as its primary technologies.

I'm curious what the Mac version uses?

I know the Mac L4 page says "The Alpha for Mac shares the same underlying code as the Windows version, but is missing much of the user interface, which needs to be coded specifically for the Mac."

Does this mean the Mac version is dependent on Silverlight in a browser?

Or does it take advantage of the Core Mac technologies (Cocoa framework, Grandcentral, Services, Scripting, Core Animation, etc.)?

Thanks,

Russ