If your document has a bookmap that includes part elements, by default their titles appear in output only with related topics, mainly siblings. You can direct DITA2Go to include the titles of their child topics as well.
To include titles of topic-heading children:
[TopicHeads] ; AddTopicHeadChildren = No (default) or Yes AddTopicHeadChildren = Yes ; TopicHeadChildHeadFormat = format for topic head children heading; ; the children themselves use the [RelatedLinks]TopicTitleFormat. TopicHeadChildHeadFormat = TopicHeadChildHead
When AddTopicHeadChildren=Yes, DITA2Go adds related child links to topic-heading topic content, provided the following is true:
[RelatedLinks] GenerateParentChild = Yes
Setting AddTopicHeadChildren=Yes overrides the value of UseChildren (see §13.1 Generating and including related links). The added items use the same formats as other related links.
To specify the text of an introductory heading for a list of child topics, in a language configuration file:
[TopicHeadText] TopicHeadChildHead = In this section:
See §8.10 Localizing output headings, labels, and names. The text shown here is the default value specified in d2g_lang_en.ini, located in directory %OMSYSHOME%\d2g\system\lang.