An account of reading USB-C cable electronic-marker information with WhatCable shows that packaging claims and capabilities recorded on a chip do not necessarily guarantee actual performance. A chip may indicate USB4 40 Gbps or high-power support, but a test device limited to 10 Gbps cannot verify the maximum speed. Uncertified Thunderbolt labeling also needs to be distinguished. Electronic markers help identify configuration, but do not independently measure wiring quality or power-handling capability; testing with compatible equipment and checking official certification remain necessary.