Yesterday Microsoft released Windows 10 Insider Preview Build 17650 to insiders on the Redstone 5 Skip Ahead ring. Microsoft added Windows Subsystem for Linux (WSL) support to the Windows Defender Firewall. Windows Defender Security Center now uses Fluent Design elements. Microsoft also fixed an issue where File Explorer would always open with the ribbon minimized, rather than remembering how you d left it. The screen will now use your customized colors and have the elements better spaced. The new design of the Security Center has been updated.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-insider-rs5-build-17650-brings-firewall-rules-for-wsl/