Coming from @yched's comment in #1875992-56: Add EntityFormDisplay objects for entity forms:
- field_ui_inactive_message()
Gee, the current code in HEAD is complete nonsense, inactive fields have nothing to do with widgets.
The message should be "%field (@field_name) field requires the %field_type field_type provided by %field_type_module module".
We need the name of the field type and its module in here, not the name of the widget / widget module.