/lib/udev/bluez-udev is in bluez 4.99-2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | #!/bin/sh -e
# /usr is not guaranteed to be mounted when udev starts
(
. /lib/udev/hotplug.functions
wait_for_file /usr/sbin/bluetoothd
exec /usr/sbin/bluetoothd "$@"
) &
|