Purpose
Agent and Web Extra Fees fall under the same category in terms of what capabilities you can set for any pre existing Extra Fee.
In the case of Agents, this screen allows you to set what Extra Fees can be selected by Agents when making a booking - "Agent API/Direct Item".
You can also specify whether Agents can enter the quantity for an Extra Fee. - "Allow QTY Entry".
For more information on both Agent and Web Extra Fees, please see the article below:
Exclusions
The Agent API Excluded Fees page allows you prevent certain Agents from applying certain extra fees.