Installed by default, meh. But I'm pretty sure it is enabled by default.
cat /etc/X11/Xsession.d/90unclutter
# /etc/X11/Xsession.d/90unclutter
# This file is sourced by Xsession(5), not executed.
if [ -e /etc/default/unclutter ]
then
. /etc/default/unclutter
fi
if [ -x /usr/bin/unclutter ] && [ "${START_UNCLUTTER}" = "true" ]
then
/usr/bin/unclutter ${EXTRA_OPTS} &
fi
