What they have found is a GFXBench listing for a Windows Phone handset. According to the benchmarks, it suggests that the device could feature a 6-inch display with a 2560×1439 resolution, along with a Qualcomm Snapdragon 820 chipset powering the handset. The benchmarks also revealed the existence of 1.5GB of RAM, a 20MP rear-facing camera, and a 12MP front-facing camera.
As far as high-end Windows 10 Mobile handsets are concerned, to date Microsoft is the only one who has made such phones with the Lumia 950 and the Lumia 950 XL, so there is a good chance that this device might be a Lumia device or even the rumored Surface Phone for all we know.
Alternatively, there are talks that HP could be making a similar high-end handset called the Falcon. However, the rumored specs indicated a 5.8-inch display and 2GB of RAM, slightly different from what the benchmarks have revealed. In any case, take it with a grain of salt as benchmarks can be faked, but if it is the real deal then we are in for a treat!