robotlegs/robotlegs-framework — comment on commit fa01f68d42f699177220555ee8b35097f45228d4
File: src/org/robotlegs/v2/extensions/mediatorMap/impl/NullV1MediatorMap.as line 14
By darscan:

There would still only be one mediator map. The IMediatorMap (and this applies to every other interface from v1) that gets injected would have an implementation that delegates to the single v2 mediator map loaded in that context.