Documentation seems to be missing a step, no output generated

[seadub]

Hi -

I've followed the steps on the README in project and the GH site but having no luck.

I have gone through steps to create combined.xml file via the build/doxygen/xml/index.xml run.

With simple ditamap file referencing the moved combined.xml file in root of project:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE map PUBLIC "-//OASIS//DTD DITA Map//EN" "map.dtd">
<map>
    <topicref format="doxygen" type="topic" href="combined.xml" />
</map>

The referenced combined.xml is not being converted into combined.dita or matching the name of the ditamap file as described in the Guide.

Output is seemingly successful with expected generation of docs, yet no .dita file or files are produced.

Detail from doxygen-generated build/doxygen/xml/Doxyfile.xml

$ cat build/doxygen/xml/Doxyfile.xml | grep XML
<doxyfile xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="doxyfile.xsd" version="1.12.0" xml:lang="en-US">
  <option  id='GENERATE_XML' default='no' type='bool'><value>YES</value></option>
  <option  id='XML_OUTPUT' default='yes' type='string'><value><![CDATA[xml]]></value></option>
  <option  id='XML_PROGRAMLISTING' default='yes' type='bool'><value>YES</value></option>
  <option  id='XML_NS_MEMB_FILE_SCOPE' default='no' type='bool'><value>YES</value></option>

More info:
Running on Macbook with M1 proc
macOS Sonoma (14.7.1)

$ doxygen -v
1.12.0
$ xsltproc --version
Using libxml 20913, libxslt 10135 and libexslt 820
$ dita --version                                                                                                                                          [17:41:03]
DITA-OT version 4.2.3
$ dita plugins                                                                                                                                            [17:41:05]
com.elovirta.pdf@0.7.2
fox.jason.passthrough.doxygen@1.3.0
org.dita-community.common.xslt@1.1.0
org.dita.base@4.2.3
org.dita.eclipsehelp@3.4.0
org.dita.html5@4.2.3
org.dita.htmlhelp@4.2.3
org.dita.index@1.0.0
org.dita.normalize@2.0.0
org.dita.pdf2@4.2.3
org.dita.pdf2.axf@3.6.1
org.dita.pdf2.fop@4.2.3
org.dita.pdf2.xep@3.6.3
org.dita.specialization.dita11@1.1
org.dita.xhtml@4.2.3
org.lwdita@5.7.0
org.oasis-open.dita.techcomm.v2_0@0.0.0
org.oasis-open.dita.v1_2@1.2
org.oasis-open.dita.v1_3@1.3
org.oasis-open.dita.v2_0@0.0.0
org.oasis-open.xdita.v0_3_0@0.3.2

Am I missing any steps?? I can't provide the project but was able to reproduce using this random project: https://github.com/TheLartians/ModernCppStarter