They come from plugins, and plugins can provided by any package, so there is no definite list.
-- Short task descriptions would improve usability https://bugs.launchpad.net/bugs/429261 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
