debootstrap
Create a basic Debian system.
TLDR
Create a Debian stable release system inside the debian-root directory
$ sudo debootstrap stable [path/to/debian-root/] http://deb.debian.org/debian
Create an Ubuntu 20.04 system inside the focal-root directory with a local mirror
$ sudo debootstrap focal [path/to/focal-root/] [file:///path/to/mirror/]
Switch to a bootstrapped system
$ sudo chroot [path/to/root]
List available releases
$ ls /usr/share/debootstrap/scripts/
