  We propose $\mathcal{T}_{13} = \mathcal{Z}_{13} \rtimes \mathcal{Z}_3$ as the
underlying non-Abelian discrete family symmetry of the asymmetric texture
presented in arXiv:1805.10684 [hep-ph]. Its mod 13 arithmetic distinguishes
each Yukawa matrix element of the texture. We construct a model of effective
interactions that singles out the asymmetry and equates, without fine-tuning,
the products of down-quark and charged-lepton masses at a GUT-like scale.
