Windows 10X is a new edition of Windows 10 designed for dual-screen devices such as the upcoming Microsoft Surface Neo, which will be available during the 2020 holiday season next year. It offers a customized interface for these devices.
Windows 10X is Windows
At its Surface event, Microsoft said that Windows 10X «supports a wide range of Windows apps,» meaning all traditional Windows desktop apps will work just like they do in Windows 10 Home or Professional. This is not a completely new operating system — it seems to be just a customized version of Windows 10 with an interface designed for these devices.
Update : Microsoft told The Verge that Windows 10X will run these traditional Windows desktop apps in a container to improve battery life. It looks like Windows 10X is based on Windows Core OS.
Optimized for dual screen devices
According to Microsoft, Windows 10X has an interface «designed and optimized for dual-screen devices like the Surface Neo.»
The Surface Neo is a dual-screen device with a hinge—like a laptop, but with part of the keyboard replaced by a screen. Alternatively, it’s like two pills connected by a hinge. If you remember the canceled Microsoft Courier concept device, it looks a lot like this.