In this field you need to enter in the postback link of your traffic source in case you need to send conversions or other values from tracker to your traffic source. Otherwise you can leave this field blank. When using traffic source templates, pay attention to the link itself. If there are parts of it that include “REPLACE”

then you should place the correct ID value (from your traffic source) in its place.
You may refer to a manager of your traffic source in order to receive postback links for AdsBridge.