As discussed on the subject page, a baseline version of the patch would completely ignore non-main slots (or require that there aren't any). Wouldn't the best short-term path forward be to rewrite the patch to do that? That would unblock further work, make it possible to roll out a smaller set of changes at a time (although I guess it makes little difference in practice as long as it's impossible to create non-main slots) and the content of that patch does not seem controversial.
