https://wccftech.com/windows-10-19h1-brings-light-theme/

Microsoft started re-releasing Windows 10 version 1809 yesterday (ISOs available here) and issued cumulative updates to several versions of the operating system, including Windows 7, 8.1 and Windows 10 versions. With all that done, the company is now pushing a brand new Preview Build to Windows Insiders in the Fast ring and this is one mega build!

Windows 10 19H1 Insider Preview Build 18282 is now available bringing a Light theme, window snip tool, improved printing experience, and several other changes and improvements to the Windows Insiders.