When the ACTION_METHOD is best-effort, and if the file /etc/powernap/action is executable, then the powernap binary will run it when called. Otherwise, powernap will run one of:
* pm-suspend
* pm-hibernate
* poweroff
depending on your hardware's capabilities, as determined by pm-is-supported(1).
You may do one of:
1) Write your own custom at /etc/powernap/action and make it executable
2) Replace /etc/powernap/action with an executable script or binary
3) Symlink /etc/powernap/action to some other executable script or binary
When ACTION_METHOD is powersave, then powernap binary will execute pm-suspend.
When ACTION_METHOD is powersave, then powernap binary will execute pm-hibernate.
When ACTION_METHOD is powersave, then powernap binary will execute poweroff.
When ACTION_METHOD is powersave, then powernap binary will execute pm-powersave and pass an argument (true) to execute all the available scripts at /usr/lib/pm-utils/power.d/ and /etc/pm/power.d/. The latter will contain scripts shipped with powernap.
On Debian systems, the complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL.