Just like well commented code makes it easy to understand, XML Schemas can be augmented with comments as well. This is done using the documentation element within the annotation element. Annotation element can be part of many of the XML Schema constructs.
Visual Schema provided a way to visualize the XML Schema definitions. Now, Visual Schemas can display the annotations as inline tooltips so that the schemas can be studied along with their comments. opentravel visual schemas are the first to get this functionality on our website.