Windows Core OS, the rumored modular version of Windows 10 that’s expected to power the HoloLens 2 and the Surface Hub 2, has never officially been mentioned by Microsoft, but more evidence about the software has now been found in an official Windows 10 support document on the company’s own website.

In case you didn’t know it already, Windows Core OS is the stripped-down, modular version of Windows that Microsoft intends to use in many of its upcoming devices with different form factors, including folding laptops like the Surface Book convertibles, collaborative displays like the Surface Hub 2 and Windows Mixed Reality devices like the HoloLens 2.