The top-level xsd:annotation element describes the schema
Its xsd:documentation child element describes the schema
for human readers
Its xsd:appInfo child element describes the schema
for computer programs; e.g. stylesheet instructions
  <xsd:annotation>
   <xsd:documentation>
    Song schema for XML and Java Example at Software Development 2001 West
    Copyright 2001 Elliotte Rusty Harold. 
   </xsd:documentation>
  </xsd:annotation>