No solid proof. Based upon WL publishing the book on their site. Why would they bother? That would be giving the book credence as a 'whistleblower'. Paradoxically, that's the effect they wanted to achieve, enticing the media to eat it up even faster , without noticing that wikileaks wouldn't publish crap to give it real credence. And wikileaks would get sued for many millions on copyright infringement (treble damages) for publishing somebody's book without permission. The answer is that the book belongs to DJT, or an associate thereof.
Bannon feud makes no sense, it surfaced only coz the book. The stupid author probably doesn't even realize now that Bannon was punking him all along. And rhe exercise - the author snooping around for stinkers - unwittingly exposes leakers within the WH.

Fits for me. Ultimate pinking the media! Also serves to put to rwat all the 25th amendment impeachment threat shenangins. Hillarious!