This is sleepd, a Debian-native package. Its home page is
http://kitenet.net/~joey/code/sleepd/

sleepd is copyright 2000-2002 by Joey Hess <joeyh@debian.org> under the
terms of the GNU GPL, version 2 or higher. On Debian systems, the full text
of the GPL is in /usr/share/common-licenses/GPL