/etc/apparmor.d/abstractions/dbus-strict is in apparmor 2.12-4ubuntu5.
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 7 8 9 10 11 12 13 14 15 16 17 18 19 | # vim:syntax=apparmor
# ------------------------------------------------------------------
#
#    Copyright (C) 2009-2013 Canonical Ltd.
#
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of version 2 of the GNU General Public
#    License published by the Free Software Foundation.
#
# ------------------------------------------------------------------
  /{,var/}run/dbus/system_bus_socket rw,
  dbus send
       bus=system
       path=/org/freedesktop/DBus
       interface=org.freedesktop.DBus
       member={Hello,AddMatch,RemoveMatch,GetNameOwner,NameHasOwner,StartServiceByName}
       peer=(name=org.freedesktop.DBus),
 |