If you saw the video about the Dark Forces Team showing Windows Phone 7′s latest “NoDo” update running on an old HTC HD2, like some of our readers you may have noticed another device show up on camera that seems to be Windows Phone 7 with an extra button on the programs listing. It’s definitely not something that was added in the NoDo release. Could the Dark Forces Team be testing a build of Mango? Is it some kind of home-brew customization?

We’ll try to find out what that button does and where it came from, but for now, what do you think it does? Could it be an easy way to find programs in your programs listing? Could it be just an on-screen shortcut to the normal Bing search app? Let us know in the comments below.

You can see the original video here.