/usr/lib/systemd/user/dbus.socket is in dbus-user-session 1.12.2-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | [Unit]
Description=D-Bus User Message Bus Socket
[Socket]
ListenStream=%t/bus
ExecStartPost=-/bin/systemctl --user set-environment DBUS_SESSION_BUS_ADDRESS=unix:path=%t/bus
|