Everything about this is invalid.

- It's a group distributor, which means there's no single feed.
- That derivation is done by the client, so for people using the yum distributor directly -- which is the likely audience for these docs -- won't have this default in place.
- The yum distributor doesn't even have a feed attribute, that's an importer concept. That relationship between feed and relative path only exists in the client who knows about both the importer and the distributor and can apply those sorts of shortcuts.