Ungraded portion of the test

Hello everybody, I was about to take the DET exam (I need it for university admissions) and at the end of the official description it said that at the end of the official portion of test, there is an ungraded essay and video interview that get sent to the university along with the graded results. I'm extremely confused as to why this is necessary and it freaked me out from taking the test. Can anyone who took the test recently explain what this looks like and what the experience was like?