Just like cURL, this is a speciality panel, designed to help you track data of the SOAP requests you make.
To activate the SOAP logging functionality you either create an instance of the included SoapClient(bedezign\yii2\audit\components\SoapClient) instead of the default one (\SoapClient) or derive from it to use as a basis for your own class.
It will take care of logging from there on.
All SoapFault’s are automatically logged an error as well. A link is provided from the Soap panel to the error. No need to add this yourself.