In Windows, I opened an .html file in the Windows Subsystem for Linux (WSL) /tmp directory (corresponding to \\wsl.localhost\Ubuntu-20.04\tmp on Windows) and found something unexpected in the address bar: file://wsl.localhost/Ubuntu-20.04/ followed by the Unix file system path to the file.
Apparently, wsl.localhost works like a webserver with directory browsing enabled, from which you can access the various WSL implementations.
That sure is handy! Any directory is automatically a simple website. Useful for some rust docs I’m drafting.
If you try to access a Windows file system, such as C:\ (/mnt/c), you should receive an error.