Check WSL version
wsl -l -v
Backup the (Ubuntu) distro
wsl --export (distribution) (filename.tar)
wsl --export Ubuntu Backup_Ubuntu.tar
wsl --export Ubuntu c:\users\xx\desktop\Backup_Ubuntu.tar
To restore a WSL distro from a backup
wsl --import (distribution) (install location) (file location and filename)
wsl --import Ubuntu d:\wsl c:\users\xx\desktop\Backup_Ubuntu.tar