public ConfigPayloadBuilder build(Element configE) {
        parseConfigName(configE);

        ConfigPayloadBuilder payloadBuilder = new ConfigPayloadBuilder(configDefinition);
        for (Element child : XML.getChildren(configE)) {
            parseElement(child, payloadBuilder, null);
        }
        return payloadBuilder;
    }
Builds a {@link ConfigPayloadBuilder} representing the input 'config' xml element.

@param configE the 'config' xml element
@return a new payload builder built from xml
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomConfigPayloadBuilder.java