Proxy in a dll that you can drop into RFT to tell RFT how to access the objects.
For example, most software has some third party customerized control which RFT cannot recongnize and return it as Generic Object. And most of the time, you will not be able to get the content of these objects.
RFT provide a Proxy API which you can develop your own Proxy which tells RFT how to access this Object and return the content (or anything you want) from the object.
Also, there are companies will do this for you for a fee.