"w64e10" opens a new hole in the closed console's ecosystem.

In previous generations, if you wanted to emulate one game console on another, you'd generally have to use some sort of jailbreak or hack to install unauthorized homebrew apps on the system. Today, thanks in part to Microsoft's Universal Windows Platform, you can download a Nintendo 64 emulator to your Xbox One directly from Microsoft's official store.

W64e10 (a port of the GNU open source Mupen64plus) has been available for Windows 10 and Windows Mobile devices for a few months through the Windows Store. The latest v 2.1.0.0.1 update to the $10 app extends that platform support to the Xbox One. That's possible thanks to the UWP program, announced earlier this year partly as a way to let developers easily bring PC apps to the Xbox One without much in the way of porting effort.
The "w64" emulator can download ROMs from a user's linked Microsoft OneDrive account, making it quite simple to import and play homebrew titles or copyrighted games (which we're sure you've personally ripped from your personal collections for completely legal backup purposes). The emulation quality is far from perfect, though. Simple games like Super Mario 64 run pretty well, but other games we tested suffered from very noticeable sound and graphics problems and struggled to run at a full frame rate.

The quality of the emulation here is less notable than the fact that such an emulator is available through the official Xbox Store in the first place. It's especially notable considering Microsoft already officially emulates select N64 titles through the Rare Replay collection. Even if Microsoft removes this new emulator from the Xbox Store (as we expect it will in short order), the app should still be usable for those who managed to download it beforehand.

This isn't the first time a developer has tried to use UWP to get an emulator onto the Xbox One. Earlier this month, the makers of the NESBox multi-console emulator announced on Twitter that they had been approved for certification on the Xbox One Store. The next day, they announced that Microsoft had asked them to remove the Xbox One support and resubmit the app.

That all suggests Microsoft frowns on running console emulators on its own console. Microsoft has yet to respond to a request for comment from Ars Technica, but the company previously told Ars that UWP apps would be tested to make sure developers don't sneak in games through a UWP program meant for productivity apps.
NESBox got around that restriction, in a way, by converting its emulator to a free HTML5 app that can run on the Xbox One through the built-in Edge Web browser. By distributing through the Windows Store, however, w64 avoids that problem, and it gets access to the Windows hardware without the added abstraction of running through a browser (though UWP apps do still run through a Windows virtual machine on the Xbox One).

Microsoft isn't the first closed platform to face this kind of emulation access issue, either. Apple doesn't officially allow unlicensed console emulators on its iOS App Store, but developers can occasionally sneak through Apple's approval net (or iOS security holes) to get emulators onto non-jailbroken devices. Now, with UWP, it looks like the Xbox One is in a similar position and that Microsoft will have to be extra vigilant to stop further emulators from sneaking onto its console.