It relates to the case:
“I am writing to inform you that the investigative team briefed by on this yesterday, and I agreed that the FBI should take appropriate investigative steps designed to allow investigators to review these emails to determine whether they contain classified information, as well as to assess their importance to our investigation,”
Just don't know if the documents are classified or of importance to the investigation. If not related then Comey would not have to supplement his testimony.
Although, I'm sure the HRC campaign will stretch the meaning to "this has nothing to do with me, I've been cleared." And right now she can get away with that.
If elected, she is going to have issues governing.