He made up an "innocuous" detail about his schedule in hopes it would be leaked. When it appeared in the media, he was able to confront the person with whom he shared it.

Fairly basic counter-intelligence tactic. There is a part of me that is surprised it actually worked. But it’s worked time and time again throughout history. Even on people far more intelligent than the career bureaucrats Bongino was dealing with. So I suppose it shouldn’t be that surprising.