Goes to show you are easy it is for internal, in-testing apps for Microsoft to go public in the Marketplace. Evidently, the beta version for Xbox Live Extras for Mango was pushed to the Marketplace today for a few hours before it was rec-called.
Labelled as such and at version 1.0, this will be the way you can purchase items for your Avatar on the phone, much like the latest v1.6 update we just received a few days ago. Now, before you become all downtrodden over the fact you missed this before it was pulled, let it be known had you downloaded it would not have run anyways as it is dependent on libraries in the Mango build. Or as Lei Tracer from Microsoft explains the situation:
“FYI, the app “Beta Xbox Live Extras” appeared in Marketplace for a few hours on 6/10. This is a beta that is intended for internal Microsoft Mango testers and should not have appeared in the marketplace, but someone threw the wrong lever somewhere so it ended up visible. If you try to run the app you won’t see anything because it depends on Mango libraries that aren’t available on your phone yet. The app is taken down now and the correct v1.6 of XLE should be visible now. Apologies for the confusion.”
Kind of funny and we're sure there was some finger pointing going at Redmond over the incident. Luckily, there wasn't anything too sensitive there that leaked out--we already know Extras exists and that it will be there in Mango too.
Source: Windows Phone Metro