Downloads, unpacks and installs Debian packages to either directly create a
 directory which can be chrooted into, or a tarball of it. In contrast to
 debootstrap it uses apt, supports more than one mirror, automatically uses
 security and updates mirrors for Debian stable chroots, is 3-6 times faster,
 produces smaller output by removing unnecessary cruft, is bit-by-bit
 reproducible if $SOURCE_DATE_EPOCH is set, allows unprivileged operation using
 Linux user namespaces or fakechroot and can setup foreign architecture
 chroots using qemu-user.