/etc/ppp/ip-down.d/netscript is in netscript-2.4 5.2.9ubuntu1.
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 | #!/bin/sh
[ ! -x /sbin/tc ] && exit 0
. /etc/netscript/network.conf
. /etc/netscript/qos.conf
ip_QoSclear $PPP_IFACE
|