Yep, that means right now you can download the Android Wear launcher and load it up on your smartphone to test out the preview. Of course, there are a few caveats here. First off, this isn't a real launcher replacement in the traditional sense, it is more of a replacement for your notification tray. Because of that, if you don't have any notifications waiting for you, there won't be anything to see or do in the Wear launcher. The other thing is that you need to be running Android 4.4 and you'll need to uninstall the Wear helper app that Google sent around to developers, if you have that installed.
The Wear launcher is quite responsive and smooth right now, which bodes well for the platform since the code won't be complete for a couple months at least. The guys at Android Police also pulled out a full set of icons, and Enrico Ros has also put up a few shots of the Wear UI, including the power down menu, and what looks like a countdown timer feature. Another interesting feature found in the code is a trigger for Daydreams, which is the screen saver function that was added to Android in version 4.2.
If you want to test out the Android Wear launcher, just head to the source.