The repo should define rules for the repo, no? You have to hope other contributors have a similar local gitignore?

For files like `.DS_Store`, technically yes. Usually the people do not have a proper global gitignore, so we put these files in the gitignore of the repo, but it’s not repo-related, it’s OS-related… Same goes for editor files. The editor is something user-related, not project related (except e.g. for iOS development where the IDE is kind of more or less imposed).