We recently found out that Microsoft will be embarking on a beta program soon for its Xbox app on Windows 10. The Xbox One Smartglass app had an open beta and Microsoft is adopting the same approach here versus a closed program like the Xbox One Preview. Now, it seems as though Xbox (beta) has made a premature appearance in the Windows 10 Store.
But it's most certainly not ready for use yet.
Full story from the WindowsCentral blog...