I checked on the README shipped with the package.
That document confused me. The Febootstrap 2.x section claims that 3.x
can build many varieties of Linux distros. :-)
IMPORTANT NOTE FOR USERS OF SUPERMIN 4.x: supermin 5.x is a rewrite of
supermin 4. It is compatible at a high level with supermin 4 /
febootstrap 3, but requires some command line adjustments.
IMPORTANT NOTE FOR USERS OF FEBOOTSTRAP 3.x:
supermin 4.x is just an evolution of febootstrap 3.x (really we just
renamed it). The previous febootstrap program is now called
supermin. The previous febootstrap-supermin-helper program is now
called supermin-helper. Apart from that they are identical, although
they will evolve and add features over time.
IMPORTANT NOTE FOR USERS OF FEBOOTSTRAP 2.x:
febootstrap 3.x is a complete rewrite. febootstrap 2.x could only
build Fedora distributions. This version can build many varieties
of Linux distros. 3.x only builds supermin appliances, it does not
build chroots. 3.x does not build cross-distro, cross-release or
cross-architecture systems. If you want febootstrap 2.x, please use
the 'febootstrap-2.x' branch from the git repository.