https://www.bleepingcomputer.com/news/microsoft/windows-subsystem-for-linux-2-wsl-2-released-to-insiders/

With the release of the Windows 10 Insider Build 18917, Microsoft has made the Windows Subsystem for Linux version 2 (WSL 2) available for testing. Now insiders can convert their existing WSL 1 distributions to the new version in order to gain access to the increased performance and compatibility.

WSL 2 is Microsoft's next version of the Windows Subsystem for Linux and includes a genuine open-source Linux kernel based on version 4.19 from Kernel.org. As it uses a real Linux kernel, Linux apps will now have full access to their normal system calls.