Installing apps via System Preferences

Hey there,

I'm running OS X Mavericks 10.9. If you drag a third party app towards the System Preferences icon, and then hold command and let go while hovering on the System Preferences icon, then System Preferences lights up with a window asking you to install the app.

Has this been around for a while, is it a bug? I haven't actually selected an option in fear of what it may do to that apps installation. Curious as to what it "installs" for a single user, since the Applications folder is system wide. Maybe they were considering an app installer during OS X development, and decided to scrap it?