I'm just posting two snippets of XInclude code that keep being expanded when I'm not looking, either by oXygen when doing search-and-replace operations or by eXist over WebDAV. They're here so I can copy/paste them back into place if it happens again.

From /data/info/sources.xml:

<!-- This XInclude tag causes the main bibliography document, BIBL1.xml, to be 
      imported into this file, where it will be processed during output. -->
                    <listBibl xml:id="fullBibliography">
                      
                      <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="/db/data/BIBL1.xml" xpointer="xpointer(//bibl)">
                        <xi:fallback><p>Unable to find bibliography elements in the BIBL1.xml file.</p></xi:fallback>
                      </xi:include>
            </listBibl>

From /data/info/credits.xml:

     <listPerson type="contributorList">
                        <!-- This XInclude tag causes a set of <person type="cont"> elements
                              from the file PERS1.xml, to be 
                              imported into this file, where they will be processed during output. -->
                              
                                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="/db/data/PERS1.xml" xpointer="xpointer(//person[persName[@type='cont']])">
                                    <xi:fallback><p>Unable to find people in the PERS1.xml file.</p></xi:fallback>
                                </xi:include>
                              
                            </listPerson>