Mystery Wire in Trunk

Was just in my trunk looking around. Found a dangling wire coming out from the grey board under the rear speakers. 2 wire, with a white connector at the end. I have a 300c, base model. Is this part of the audio system, prewired for the upgrade? Might pull off that shroud later on to take a peak where its coming from. At work now so itll have to wait. Any help will be appreciated!