The GFXBench site listing also reveals that it is a “msLumia prototype” hinting that it belongs to a new Lumia prototype. Now, it is quite difficult to tell what this devices is, but may be Microsoft is testing some Lumia device destined to land in 2016. May be the Surface Phone.
We will keep you updated if we come to know more.
Thanks xxDarkAngelCraftxx for the tip. Cheers!!