Microsoft appears to have been developing a new Lumia device with a camera bump that’s bigger or equal in size to the 41-megapixel Lumia 1020. Leaked photos from a Chinese auction site show a device identified only as "Nokia RM-1052" running Windows Phone 8.1 alongside 2GB of RAM and what appears to be a 5-inch 1080p display. The camera bump is the obvious addition here, dominating the rear of this device with its aluminum body.

While it’s possible this device could be an elaborate fake, there are signs that suggest it’s simply a Windows Phone prototype. At the rear of the mysterious handset there is Nokia prototype text, and the device looks unfinished in places. The body seems to be aluminum, but there’s a plastic strip at the bottom of the device, an addition that looks odd but may assist with radio signal strength. Nokia uses a similar strip on its basic 515 handset, and the company has also previously combined polycarbonate with aluminum for the Lumia 925 design.

This mysterious device could also be the canceled "Nokia McLaren" handset that was supposed to showcase Microsoft’s Kinect-like Windows Phone gestures. On-screen Windows Phone buttons, instead of dedicated physical buttons, on this leaked handset could also back up that theory, as McLaren was supposed to support floating off-screen gestures that don’t require owners to physically touch the display. Microsoft is continuing to investigate its "3D Touch" technology, but the company canceled its plans to release McLaren earlier this year.

Although McLaren was described previously as a handset that would "largely be seen as a Lumia 1020 successor with a similar hump in the rear casing for a powerful camera," it’s not clear how powerful the camera is in this leaked prototype. While the camera is large, the device is fitted with an LED flash rather than the xenon flash found on the Lumia 1020, and the lens appears to lack a mechanical shutter. We’ve reached out to Microsoft for comment on this prototype Windows Phone, and we’ll update you accordingly.