Good questions!
As described in Revised SGB proposal for voting on technical issues in the “Who can vote” section, for the other modules we will initially start with module = repository on stan-dev, but it probably makes sense to group certain repositories together. We wanted to get the initial plan out without getting bogged down in how to group repositories together, but we definitely think this is something that should be amended going forward (e.g., grouping some interface repositories together).
This is also something we discussed but we didn’t feel like we had enough information on how this would play out to make a decision in advance. Currently there’s no upper limit on the size of any of the modules, but we recognize that this particular module has the potential to grow faster than the others (there are more ways to qualify) so questions related to the relative voting power of the different modules may need to be addressed by this SGB or the next one depending on the growth we see in the various modules.
Yeah this is tricky, but I don’t think it’s necessarily much different than what we have already been doing. Like you say, there’s some notion of “significant PR” but there’s no formal definition of that (nor would it be easy to come up with one in my opinion). Similarly, there’s no formal definition of what constitutes a substantial enough contribution for this module. We have historically left it up to other people in the “module” to decide if contributions have been substantial enough (e.g., developers in the math library have decided if new contributors to the math library have made substantial enough contributions to be labeled “developers”), and for this new module we envision something similar.
Anyway, thanks for the questions/feedback and let me know if I need to clarify more!