So, in the transcript Papa D names who (Person A) is, the mysterious person calling him from the Trump campaign wanting to know where he was. Papa D suspected Bert Mizusawa was feeding the Deep State info from within Trump campaign.
pg 78
https://dougcollins.house.gov/sites/dougcollins.house.gov/files/Papadopoulos%20l10.25.18%20Interview%20Transcript_Redacted.pdf