<hometopic>heading topic text begins here ...
There is only one home topic for a help volume. It comes after the meta information (<metainfo>) and before the first <chapter> or <s1>.
The <hometopic> element does not support an author-defined ID. The HelpTag software assigns the predefined ID _hometopic.
To create a hyperlink to the home topic, use this syntax:
<link hyperlink= "_hometopic">...<\link>.