It looks like Microsoft is planning to introduce a new version of its 'hero' desktop wallpaper for Windows 10.
The current version made its debut in June 2015, shortly before the OS was officially released a few weeks later. At the time, Microsoft was particularly proud of the fact that the image had been created using a physical model with fog and laser effects; it even shared a short music video in which the Windows logo model played a starring role.
The new version of the wallpaper was spotted by Windows Central in Windows 10 Cloud build 15046, and as you can see, its design appears somewhat less complex than that of the original. MSPoweruser speculates that the updated wallpaper might be unique to Windows 10 Cloud, and that its simplified design is intended to align with the more 'lightweight' nature of that OS version, which will only be able to run apps downloaded from the Windows Store.
It remains to be seen if Microsoft intends to use the new wallpaper solely for the Cloud SKU, or if it will be included with all Windows 10 versions in the future. The wallpaper is available in a range of sizes from 1024x768px, all the way up to 4K (3840x2160px); you can download it from here to try it out on your PC.