Arch Linux added it a while ago: https://gitlab.archlinux.org/archlinux/packaging/packages/openssh/-/blob/main/ssh-agent.service Relevant Arch wiki entry: https://wiki.archlinux.org/title/SSH_keys#Start_ssh-agent_with_systemd_user Having this could be useful in order to automatically start ssh-agent at user login.
I've been using a similar unit on my own Gentoo systems.