It doesn't appear that they show up on the bank statements.
They seem to be much like a CC split cash advance, where the loan is paid back from the sales on Amazon. Which means that their Amazon profit margin is reduced. I think they take a lien on the inventory as collateral.

Is it called a "position" for a funder? MCA, Bluevine, Funding Circle, Bank, etc...
Does Amazon loans file a UCC? How would a funder know about it?