Factory OS
docs.microsoft.com
docs.microsoft.com
There’s some potential for uses outside of OEM scenarios, but it’s understandably not very polished for general use.
Still, now that the upgrade work has been been done… feels like they could release a new Windows IoT Core version based on this pretty easily.
Architectures that it supports are: 32-bit Arm, 64-bit Arm and 64-bit x86.