Question: "... "actions" can be hooked up to change the behaviour of a particular device.."

The Readme say:

In addition to those 2 or 3 modes (depending on the system), "actions" can be hooked up to change the behaviour of a particular device. For example, this can be used to disable the fast-charging for some USB devices when in power-saver mode.

How do we hook up actions? On my AMD 7840U, I want to

echo low > /sys/class/drm/card1/device/power_dpm_force_performance_level

when enter power save profile

and reset it to auto on other profiles, and if the system boots in power save, it should apply that setting.

Despite what the Readme says about hooking up actions, I can't find any further documentation on that.