code: private Url parseUrl(Node el) {
          return new Url(
                  nodeAttribute(el, TAG_VAR_ATTR_NAME, Url.DEFAULT_NAME),
                  nodeAttribute(el, TAG_ATTR_GHOST, PatternElement.DEFAULT_GHOST_VALUE),
                  nodeAttribute(el, TAG_URL_ATTR_LOCAL, Url.DEFAULT_LOCAL),
                  nodeAttribute(el, TAG_URL_ATTR_SCHEMALESS, Url.DEFAULT_SCHEMALESS)
          );
      }
docs: Parse an URL tag.
  
  @param el tag element
  @return Configuration URL.