  We study rack and quandle coverings from a universal algebraic viewpoint and
we show how they can be understood using the notion of strongly abelian
congruences. We provide an abstract characterization of several particular
types of covering extensions, such as central and abelian ones. We give a new
characterization of simply connected quandles and we show that the categorical
notion of normal extension coincides with the notion of central covering. We
answer several questions from the papers of Clark, Saito and Vendramin
\cite{CS} and \cite{CSV} about identities preserved by quandle coverings.
