Either Microsoft open source it for Phone Company to develop custom UI for their phone (like android... sigh...), let all Phone Company to create custom UI for their own phone, so it look alike on their same phone (like HTC One (M8) for Windows and Android, making them both looks similar in all way).
Or this is 100000000000000000% fake
it looks like a android custom ROM for me, why? 3x3 tile has lyrics running, interactive button. through, i hope interactive tile and dynamic tiles (for running lyrics when song is running) are featured in Windows Phone...