`journalctl` captures all syslog priority levels; filtering happens at query time via `-p <level>`. The existing monitor log command always shows all priorities.
A `monitor log filter <priority>` sub-command lets operators tail the journal at a specific minimum severity without having to remember journalctl flags.
`journalctl -p <level>` shows messages at that level and above (i.e., lower numeric severity values are always included — warning also shows err, crit, alert, emerg).