whoever installed the exhaust probably installed the "Emulator" but didn't feel like pulling the guide tube out or figured you might need it if later you put the factory exhaust back on to sell it or something like that..
pulling it is pretty involved as it's tie wrapped in a number of places and buried under a pill of wires in a few areas where it's routed... I would just tie wrap it off somewhere to keep it from just hanging like that and not worry about it.
H2