Defaults parameter on a form and fieldset. That is, when you have many formfields and you have the ability to have “defaults” object on the form or fieldset, where you can add the default config values for that form. F.e.
view : 'fieldset', label : 'Algemeen', body : { defaults: { labelWidth : 75, .more default values. }, rows : [{ view : "text", name : "naam", label : "Naam", required : true }, { view : "text", name : "telefoon", label : "Telefoon", required : true }, { view : "text", name : "email", label : "Email", required : true, validate : "isEmail" } ....