/proc/thread-self/root/lib/sysusers.d/ Current File: //proc/thread-self/root/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"