Wondering about fields in modx_documentgroup_names table

What are the fields "private_memgroup" and "private_webgroup" in this table for? Are they used at all right now?

I think those are left over from Evo and not used, but I could be wrong. If you have resources groups and ACL entries for them, and those fields are all empty in the DB, I think it's safe to assume that they're not used.