System Prefernces > Software Update: Mystery Updates!

Hi I have a MacBook Air mid 2011 with OS X 10.7.2 Lion. Just out of curiosity, I clicked on the "Software Update" preference pane in System Preferences. To my surprise, i found updates that I never even installed on the computer. Most specifically, I saw a "Mac OS X Update. The version number said 10.6.5. That's OS X Snow Leopard. But the minimum OS for my mac is OS X 10.7 Lion. The date says it's from 2010, which is even weirder because the mac was made in 2011. There are 3 other updates, being OS X 10.6.6, 10.6.7, and 10.6.8 v1.1. There are also a bunch of other updates from 2010 for OS X Snow Leopard (for example there's one titled "Java for Mac OS X 10.6 Update 3"). The strangest thing is that I have a 2010 iMac that had OS X Snow Leopard installed (it's now on Mavericks). I don't see the OS X Mavericks Update on my MacBook Air though. Can somebody explain to me what happened? Did the two computers connect on the network or something and sync updates? Any help would be much appreciated.