On 2007-10-27 srahtz normalized the use of alien namespaces in the TEI Guidelines (r3833). Back then, a child of <egXML> that was in an alien namespace showed up with its prefix, without any visible binding of that prefix. This meant that the first example of section 20.4 showed up as having <xi:include> elements, and the reader was not aware that “xi” was (inappropriately, but necessarily) bound to the namespace “http://www.example.org/ns/nonTEI”. That is, the reader of the processed Guidelines saw a (mildly) incomplete, but correct example.
But now this example shows up without prefixes, and with each <include> element having an explicit xmlns= attribute that shows the example namespace, leaving readers with a complete, but erroneous example.
 This is inappropriate, because the point of the example is to demonstrate the use of the <include> element in the “http://www.w3.org/2001/XInclude” namespace. It is necessary because we *can’t* use the <include> element from the “http://www.w3.org/2001/XInclude” namespace, lest it be interpreted as being an instruction for inclusion during processing of the TEI Guidelines.