With the release of snapd 2.61, a system-username of `_daemon_` is now supported and preferred over `snap_daemon`. https://github.com/snapcore/snapd/pull/13052 A value of `_daemon_` cannot currently be parsed in snapcraft (7.5.3.post117+git2d596621) without using `passthrough:` For example, the following:   system-usernames:     _daemon_: shared produces the following error: Issues while validating snapcraft.yaml: The 'system-usernames' property does not match the required schema: '_daemon_' is not a valid system-username.