'Mercury' is the code name of a large Xbox Store update, coming soon

[Windows Central]

If you've seen images of an app called "Mercury" floating around on Xbox communities, here's what we know about it so far.
Recently an Xbox Insider Program update made an app called "Mercury" available to a few testers, with a splash screen that just reads as "Coming Soon. Please upgrade to access the latest and greatest."
I received a few messages about it, and thought I'd try and find out some more about what it is and what it does, since some had speculated that it might be something related to Project xCloud.

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