Windows Subsystem for Linux is an optional feature, which you can choose to enable or not.

Microsoft confirmed Friday that it will ship Windows Subsystem for Linux 2 in the upcoming Windows 10 20H1 (2004) release, though updates will be handled though Windows Update, and not the app.

As we noted in our review of Windows 10 20H1, Windows Subsystem for Linux 2 (WSL2) is an optional feature that you can add to Windows, or ignore entirely.
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https://www.pcworld.com/article/3532355/how-the-linux-kernel-will-work-in-windows-10s-next-big-update.html