Ubuntu "flavors" (*buntu in the name) all use the same package pool directly, and users sophisticated enough to post a bug report are generally aware they're using an Ubuntu version.�� I support all of them.
Ubuntu derivatives (such as mint and elementary os) might use binary copies of the packages, might do rebuilds, and might replace certain packages.�� They should be listed as either "other" or their own category if they're popular enough for bugzilla purposes (mint in particular).�� I don't support them.