when the transponder that under the heat sink blew out that creates an electrical short. the electrical short causes more current to flow threw the wires than the wire gauge (diameter) can handle so in turn the wires get hot and the insulation starts cooking and melting off that is what you have circled in your screenshot wire insulation residue. the case itself is not made of aluminum but a type of plastic possible polyvinyl chloride (pvc).
United States