They are relevant witnesses, simply because they were involved in the conditions that allegedly led to the so called whistleblowing complaint being filed as a matter of pure politics. Much of it in disregard for the laws in place.
The director of national intelligence won’t let anyone see the original complaint!
So the “whistleblower” who ostensibly started this BS is not a legitimate witness and the interviewer does not say WTH? These people are just shameless.