Frage Radio wiring?

Hi everyone. I've finally decided which radio to upgrade to. It's an Atoto S8, single din with a floating screen. Started to remove the existing radio today and in addition to the wiring harness (which Atoto provide a connector  for) I noticed two addtional wires: one black, one white. These weren't attached to the existing radio. Has anyone any idea what they connect to in the van itself? Cheers. Ian