Linux puskom-ProLiant-DL385-Gen10 5.4.0-150-generic #167~18.04.1-Ubuntu SMP Wed May 24 00:51:42 UTC 2023 x86_64

//usr/lib/sysusers.d/dbus.conf

 # sysusers.d snippet for creating the D-Bus system user automatically
# at boot on systemd-based systems that ship with an unpopulated
# /etc. See sysusers.d(5) for details.

u messagebus - "System Message Bus"