It's not really a fee. It's just the price they charge you for data transfer to external systems. This is known as Data Egress charges and all cloud providers I know off has it. The cost of egress will depend on which service you are using. Some services have lower data transfer out costs, some have higher, etc..

There is no departure fee. As others have pointed out, this is simply data transfer.

I believe the parent is referring to the price of the bandwidth that would be required for transferring data from AWS to somewhere else.