Windows 10 build 17661 (rs onecore dep uxp dev.180502)

Windows 10 build 17661 (rs_onecore_dep_uxp_dev.180502) is an unleaked build of Windows 10 October 2018 Update. It was showcased in the session "What's New for Windows UX Developers: Fluent and XAML" at the Microsoft Build 2018 conference, as well as in the video "Exploring the Fluent Design System" for the series "On .NET" on Channel 9.