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, fakechroot or proot and can setup foreign architecture chroots using qemu-user.