Search notes:

/mnt/wsl/

/mnt/wsl is a tmpfs filesystem: 
$ mount | grep  '/mnt/wsl\>'
none on /mnt/wsl type tmpfs (rw,relatime)
As per this comment, WSL creates different mount namespaces for distributions, and /mnt/wsl is a mountpoint that all namespaces share.

resolv.conf

At least in my WSL installation /etc/resolv.conf is a symbolic link to /mnt/wsl/resolv.conf.

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