/etc/profile.d/dbus-source.sh is in ubuntu-touch-session 0.108+16.04.20160407-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | # source dbus address from new location
[ -e $XDG_RUNTIME_DIR/dbus-session ] && . $XDG_RUNTIME_DIR/dbus-session
[ -n "$DBUS_SESSION_BUS_ADDRESS" ] && export DBUS_SESSION_BUS_ADDRESS
|