Comment 45 for bug 1718227

For ethtool the if-up.d script is actual integration of hardware settings from ifupdown, i.e. it is parsing ifupdown settings in order to get them applied to the device via ethtool.

https://salsa.debian.org/kernel-team/ethtool/-/blob/master/debian/ethtool.if-up?ref_type=heads

This is not relevant for Netplan/systemd-networkd as it can control such ethtool settings itself (e.g. via .link files).