Webservice - Confusing article response

[pjdevries]

I am somewhat confused by the response of v1/content/article(s). In the data attributes section see the following fields:

• created
• created_by
• modified
  In the relationships section I see:
• created_by
• modified_by

My questions are:

• Should there not be a modified_by in the attributes section as well or is the created_by in the attributes section redundant/obsolete?
• Why the redundancy, i.e. why similar attributes in both the attributes and the relationships section?