code: function warn(oElement) {
  				if (bWarning) {
  					if (!bCallerLoggedForWarnings) {
  						bCallerLoggedForWarnings = true;
  						Log.warning("Warning(s) during processing of " + sCaller, null,
  							sXMLPreprocessor);
  					}
  					Log.warning(
  						getNestingLevel() + Array.prototype.slice.call(arguments, 1).join(" "),
  						oElement && serializeSingleElement(oElement), sXMLPreprocessor);
  				}
  			}
docs: /*
  Outputs a warning message with the current nesting level; takes care not to
  construct the message or serialize XML in vain.
  
  @param {Element} [oElement]
  any XML DOM element which is serialized to the details
  @param {...string} aTexts
  the main text of the message is constructed from the rest of the arguments by
  joining them separated by single spaces