You can see the raw message with `-o verbose` (or json/json-pretty/...). You can also pick just the fields you want with `--output-fields`.

  $ journalctl -f -u sshd

  Feb 15 13:21:56 vm sshd[4844]: pam_unix(sshd:session): session opened for user user(uid=1000) by user(uid=0)

vs

  $ journalctl -f -u sshd -o verbose
 
  Thu 2024-02-15 13:21:56.886724 UTC [...]
    PRIORITY=6
    _SYSTEMD_SLICE=system.slice
    _BOOT_ID=8e87dffc55844df1b122cfa31010b1df
    _HOSTNAME=vm
    _RUNTIME_SCOPE=system
    _UID=0
    _GID=0
    _CAP_EFFECTIVE=1ffffffffff
    _TRANSPORT=syslog
    SYSLOG_IDENTIFIER=sshd
    SYSLOG_PID=4844
    SYSLOG_TIMESTAMP=Feb 15 13:21:56 
    _PID=4844
    _COMM=sshd
    _EXE=/usr/bin/sshd
    _CMDLINE="sshd: user [priv]"
    _SYSTEMD_CGROUP=/system.slice/sshd.service
    _SYSTEMD_UNIT=sshd.service
    _SYSTEMD_INVOCATION_ID=4065f778bd534ab98f1849d858d0f49e
    SYSLOG_FACILITY=10
    MESSAGE=pam_unix(sshd:session): session opened for user user(uid=1000) by user(uid=0)
    _SOURCE_REALTIME_TIMESTAMP=1708003316886724