I think this has been discussed before, but I cant tell if there is an official rule for that (maybe it could be added to the wiki).

So let's say I have a patch which removes the Collection arithmetic protocols (332). Now this protocol is still quite nice and we can offer it as an extension package for those who need it. Where should I put this Collection-Arithmetic package? In its own squeaksource project? Or is there a project for extra packages for Pharo?