I'm interested in packaging (as my first package!) Lxdoom. However, it is a non-free package - I'm not so concerned about that, it's only a game - and what's more, it depends on the registered .wad files of Doom, Doom 2, or another id game. Is it allowable to include lxdoom in Debian? I note that the Policy manual does allow 'contrib' to depend on packages which aren't in Debian at all. Can this be done?