Microsoft has released a new Insider build in the "19H1" branch of Windows 10. The "19H1" branch is the next big update coming after Redstone 5 and is projected to be finalized in the spring of 2019 according to Microsoft’s typical release schedule.
Today's release of Windows 10 Preview Build 18219 is only available to Insiders in the Skip Ahead Ring whose availability was officially closed as of yesterday. This means that unless you had previously selected the Skip Ahead build, you will not be able to get builds form the 19H1 branch until they reopen it.
Windows 10 Preview Build 18219 comes with minor improvements associated with Narrator and the rest are mostly bug fixes.
Of particular interest is a known issue with the Windows Subsystem for Linux (WSL) feature that allows you to run different Linux distributions within Windows 10. These bugs may cause hangs when using WSL, which can be fixed by rebooting Windows 10.
It is not known if these hangs only affected the WSL or if Windows itself freezes. If you are a regular user of WSL, Microsoft suggests that Insiders skip this branch in order to avoid these issues.
Microsoft has updated the narrator to include an improved version of the Scan Mode feature, which allows you to navigate apps, email, and web sites using the keyboard's arrow keys and other keyboard shortcuts.
The full list of Narrator changes and improvements can be found below.
A complete list of the changes, improvements, fixes, and known issues for build 18219 can be found here.