Manoj Srivastava has uploaded reference policy packages to Debian. If you’re going to setup a SELinux system with Debian, I’d recommend you to use the new policy packages (which are currently named “selinux-policy-refpolicy-”, but that might be shortened to selinux-policy- or so sometime, I guess)

This is basically the only SELinux policy tree actively maintained.

The old policy, packages as selinux-policy-default, is discontinued upstream.