Immutable reference point for the corrigendum to

  Colquhoun, D., and R. Lape. 2012. Allosteric coupling in ligand-gated
  ion channels. J. Gen. Physiol. 140:599-612. doi:10.1085/jgp.201210844

This tag marks the same commit as v0.5.1. It exists so that the
reproduction notebook can cite a version that will never be moved or
re-pointed, independently of any future decision about the v0.5.1
release itself.

The notebook lives at

  https://github.com/DCPROGS/ColquhounLape2012-reproduction

and has been executed end to end against this commit in a clean virtual
environment (Python 3.13, NumPy 2.5.1, SciPy 1.18.0), with no cell
errors and with every scalcs module resolving to the installed package
rather than to a development checkout. All twelve published quantities
it checks are reproduced to within 0.13 %.