The 'DFP' (source) interrogates the cable, and when it advertises its capabilities to the 'UFP' (sink) it will only include what is mutually supported by the so

The 'DFP' (source) interrogates the cable, and when it advertises its capabilities to the 'UFP' (sink) it will only include what is mutually supported by the source and cable. In theory I believe the 'UFP' can also query the cable once in a contract, but not sure if this is common/ever done, I guess this capability mostly exists to inform the user if the cable they are using is insufficient.