@ehelms, the approach taken here is based upon the approach previously taken for controllers such as system groups (e.g. https://github.com/Katello/katello/blob/master/app/controllers/katello/api/v2/system_groups_controller.rb#L69).

The idea is to support multiple routes that result in listing a set of objects based upon some context.   (E.g. list errata by repo, by content view + filter...etc.)  In each case, the list of objects should contain the objects in the same format.

The alternative might be to add an action to other controllers (e.g. filters_controller, action: errata); however, that would simply duplicate some of the logic that is here and could potentially diverge over time.

It has been expressed to me in multiple PRs now that there is a goal to have unnested routes (e.g. /errata?repository_id=1).  If that truely is a goal, a centralized location like this is necessary, have /errata directed to multiple controllers.