Scripted, for specific words. But that also makes it clear what to expect. Practice with the available stories and you are set. All questions are tell me about a time style so prepare well. The system engineering questions are straightforward but prepare to dig deep. Overall, so much info is available that with enough practice you should be ok

Strenuous and long. 2 pre interviews followed by 5 interviews in the day testing all competencies. Interviewers were great. The process was very long and unfortunately missed out to an internal candidate.