Need help unmapping function key.

Shortly after I purchased my MacBook Pro, I decided that it would be handy to have the function mapped to trigger expose. Over the years however I've found it to be more a nuisance than helpful. My problem is that I used a 3rd party application to do so, and cannot remember the name of said application. I've searched my machine several times over in an attempt to find the application, and have had no luck in doing so. Therefore I need help in either finding the application, or using a work around to disable it.

TL;DR Mapped function key to expose using 3rd party application, and now cannot unmap it.