Canonical has provided security updates just for the packages in "main" and the security updates for the rest were provided by community maintainers on a best-e

Canonical has provided security updates just for the packages in "main" and the security updates for the rest were provided by community maintainers on a best-effort basis. With Ubuntu Pro, Canonical now provides security updates for more packages than it used to, otherwise. Disclaimer: I work for Canonical but have nothing to do with the distribution or Ubuntu Pro. And I am not speaking on behalf of the company.