Hello all, Elo,
Notice that the solver is not in the ET! But I will gladly support the effort of including it, if needed, as well as answer the questions of those who simply want to use it.
Uhm, that is indeed correct. The thorn is not in the ET and any user should consult the documentation in the thorn repository for license and citation policies. I have added the URL, version information etc to the "thorns we know of" page on the wiki which lists non-ET, public thorns: https://docs.einsteintoolkit.org/et-docs/Thorns_we_know_of Please feel free to amend as needed.
Yours, Roland