  Experiments on bilayer graphene unveiled a fascinating realization of
stacking disorder where triangular domains with well-defined Bernal stacking
are delimited by a hexagonal network of strain solitons. Here we show by means
of numerical simulations that this is a consequence of a structural
transformation of the moir\'{e} pattern inherent of twisted bilayer graphene
taking place at twist angles $\theta$ below a crossover angle
$\theta^{\star}=1.2^{\circ}$. The transformation is governed by the interplay
between the interlayer van der Waals interaction and the in-plane strain field,
and is revealed by a change in the functional form of the twist energy density.
This transformation unveils an electronic regime characteristic of vanishing
twist angles in which the charge density converges, though not uniformly, to
that of ideal bilayer graphene with Bernal stacking. On the other hand, the
stacking domain boundaries form a distinct charge density pattern that provides
the STM signature of the hexagonal solitonic network.

Mesoscale and Nanoscale Physics;Disordered Systems and Neural Networks;Materials Science