When you package Eclipse Help in a .jar file, the .jar file must include a Java manifest, MANIFEST.MF. DITA2Go can create this file for you, and does so by default when UseManifest=Yes; see §21.3.1 Specifying a Java manifest file for Eclipse Help.
To prevent DITA2Go from creating MANIFEST.MF when UseManifest=Yes:
[EclipseHelpOptions]
; WriteManifest = Yes (default, always write, even if it exists)
; or No (customized, write only if not found)
WriteManifest = No
When WriteManifest=Yes, DITA2Go creates MANIFEST.MF in the project directory; if this file is already present, DITA2Go overwrites it.
When WriteManifest=No, DITA2Go creates MANIFEST.MF only if this file is not already present in the project directory; DITA2Go does not overwrite an existing MANIFEST.MF. This setting allows you to customize MANIFEST.MF outside of DITA2Go, without losing your customizations during subsequent conversions.
To specify that your plug-in must run as a singleton:
[EclipseHelpOptions]
; UseSingleton = No (default) or Yes (add "; singleton:=true" after
; PluginID in manifest file)
UseSingleton = Yes
When UseSingleton=Yes, DITA2Go adds “; singleton:=true” after the value of Bundle-SymbolicName in MANIFEST.MF.