  The work contains a detailed study of the scaling limit of a certain
critical, integrable inhomogeneous six-vertex model subject to twisted boundary
conditions. It is based on a numerical analysis of the Bethe ansatz equations
as well as the powerful analytic technique of the ODE/IQFT correspondence. The
results indicate that the critical behaviour of the lattice system is described
by the gauged ${\rm SL}(2)$ WZW model with certain boundary and reality
conditions imposed on the fields. Our proposal revises and extends the
conjectured relation between the lattice system and the Euclidean black hole
non-linear sigma model that was made in the 2011 paper of Ikhlef, Jacobsen and
Saleur.
