Using ${dita.temp.dir}/fullditatopic.list generates unused .html file

[ToshihikoMakita]

DITA-OT standard HTML5 plug-in uses custom elements. This selects correct topics needed to generate. However it does not accept Saxon debugging feature settings such as:

<factory name="net.sf.saxon.TransformerFactoryImpl">
    <attribute name="http://saxon.sf.net/feature/timing" value="true"/>
    <!-- Suppress namespace warning -->
    <attribute name="http://saxon.sf.net/feature/suppressXsltNamespaceCheck" value="true"/>
    <!--Assert-->
    <attribute name="http://saxon.sf.net/feature/enableAssertions" value="true"/>
    <!-- Trace -->
    <!--attribute name="http://saxon.sf.net/feature/traceListenerClass" value="net.sf.saxon.trace.XSLTTraceListener"/-->
</factory>

This is very inconvenient. So I'm using ${dita.temp.dir}/fullditatopic.list. This list contains unused topic files such as conref target only file.