I have systems that would not have python installed except etckeeper
depends on it. The dependency is for brz if I understand correctly.
However, etckeeper does not use brz by default, and its dependencies
let the user choose their vcs without pulling in all the dependencies of
all the others, except for in this case.

Since the python module needs to be registered using python in order to
be used, and the postinst does that, just removing the dep would be a
problem. Maybe split the package and replace depends | brz | with
etckeeper-brz?