  In their Letter, Borda, Cai, and de Koning report the results of ab initio
simulations of dislocations responsible for the giant plasticity. The authors
claim key insights into the recent interpretations of (i) the giant plasticity
and (ii) the mass flow junction experiments. The purpose of this Comment is
clarifying the role of dislocations in the mass flow in conjunction with
explaining that the part (ii) of the claim is misleading.
