Microsoft has recently updated its Windows Store policies which completely block all emulation of game systems from Windows Store on all platforms. The policies were published by the company last month and now the company has started to take action on the Emulators.
The Universal Emulator which was denied an Xbox release has now been completely pulled from the Windows Store. The reason behind is said to be related to the upcoming Xbox Live Creators Program which is part of the unification of Xbox Store and Windows Store. This is mainly focused on getting UWP Xbox Play anywhere on the store by makes it easier for submission.
Currently there are some game emulators still available in the Windows Store but are made for Windows 8 and not UWP emulators. The UWP emulators had to go through ID@Xbox for a release on the Xbox one which brings it to rest of the devices running Windows 10.