Devs getting stuck into Windows 10X on Surface Neo will have to tussle with UWP
https://www.theregister.co.uk/2019/10/03/windows_10x_for_developers_headache_or_opportunity/
Microsoft has gone public on a new range of Surface hardware, the most intriguing being two foldable devices – one an Android phone and the other running a new variant of Windows, Windows 10X. The devices are prototypes, with general availability planned for late 2020.
Windows 10X is not exclusive to Surface. Microsoft's own hardware line-up has always been about driving the company's OEMs to deliver improved Windows devices, as well as being an important product line in its own right. So we can expect other dual-screen Windows 10X devices from the usual crowd – vendors such as Asus, Lenovo, HP and Dell.