There are many middleware libraries out there that developers are using to build great Android apps. The app may have been released some time ago in the Google* Play store and the library may have only supported arm devices at that time.
Did you know you could reach a larger audience for your app by adding native x86 support? Building for x86 yields the best performance and experience for Android x86 based devices while not breaking compatibility with arm devices. Many of these libraries have been updated and build for x86 by default. There is a great article that details how to do this further at the link below.