Hotplug - OpenWrt Wiki
https://openwrt.org/docs/guide-user/base-system/hotplug28.07.2021 · Hotplug Procd (the init system and process management daemon) executes scripts located in /etc/hotplug.d/ when certain events happen, like for example when an interface goes up or down, when a new storage drive is detected, or when a button is pressed. It can be very useful with PPPoE connection or in an unstable network, or to use hardware buttons.