The proofing formats (and indeed all the formats out there) are generally made as separate projects by separate authors, so there isn't a global repository of all of their code and it's unlikely that there ever will be. However, collecting links to all the various formats and proofing formats and placing them on the wiki (and maybe their individual repositories) isn't a bad idea at all--there are definitely a couple formats I'm aware of that aren't listed on the wiki yet.