[$] Debian's AWKward essential set

The Debian project has the concept of essential
packages, which provide the bare minimum functionality considered
absolutely necessary (or 'essential') for a system to
function. Packages tagged as essential, and the packages that are
required by the set of essential packages, are always installed as
part of a Debian system. However, Debian's packaging rules do not
require developers to explicitly declare dependencies on that set of
packages (the essential set) but they can simply rely on the fact that those
will always be present. That means that changing the essential set, as
the project may wish to do occasionally, is more complicated than it
should be. This came to light recently when a Debian developer asked
what might be required to remove mawk to slim down
the project's container images.