When a heading has subheadings under it (so that it becomes a “book” in WinHelp), WinHelp provides no way to get from the contents entry to any text that comes after the heading and before the first subheading. Therefore DITA2Go adds a dummy topic “page” called (by default) “Overview” to permit access to this otherwise orphaned text.
You can change the name of this dummy topic to something other than “Overview”; for example, to name it “Introduction” instead:
[HelpContents] CntBStyleText=Introduction
If you do not want to provide access to any text in this area, you can change the setting for the heading from V to H, keeping the same level number; for example:
[HelpCntStyles] Heading1=H1
Then there would be no “Overview” for text that immediately follows a Heading1 paragraph. You would be able to access the text between that heading and the next only as part of a browse sequence; see §17.13 Creating browse sequences.