Hi again Patrick,
this aspect varies site by site. For this reason the content data source can be disabled from the HTML sitemap presented to users leaving only a quick navigation menu.
There is also another option, with an effect that must be evaluated based on the way that menu are built.
You can merge the content data source elements with the one of the menu, if not using the mindmap layout, to build a unique tree.
In the screenshot below i highlighted the 2 parameters to accomplish what i said above.
There is also another option, if you want to differentiate the elements included in the content data source for HTML from the XML one, you can create a copy of the content source and exclude categories, articles etc.
The elements included in the HTML sitemap can be configured in different ways.
PS: i'm not sure if i asked you to contact me by email, but i think so. Please contact me by email for further questions.