Systemd-resolved is present by default in Ubuntu 18.04. Resolvconf pkg is not.
From reading around, systemd-resolved provides name resolution while resolvconf provides multi-client access to update the configuration of name resolution.
The question is: do they both happily co-exist? Does resolvconf know about systemd-resolved and update its configuration? Or instead, does systemd-resolved somehow learn about updates to name resolution files that resolvconf has done?
I get suspicious when I see that resolvconf symlinks to /run/resolvconf/resolv.conf whereas systemd-resolved symlinks to /run/systemd/resolve/resolv.conf. Seems conflicting to me.