nzgz you see in the screen shot would relate to your form when it is published. look at a form you have deployed and under the LINK button to see how it relates to the other methods of linking – in the ’embed’ and ‘preload’ links seeing the similar reference to the form.
the ‘params’ of course will relate to the parameter index you have defined within the Get External Call Parameter for the fields you wish to populate
Util.js is part of the actual application and not relevant in the External Call. The only time you’d refer to this file is in the OnPremise version where you would be ‘customising’ in terms of the standard Perfectforms logo’s