LibreOffice can build three kinds of help output from helpcontent2:
Both local help variants can be included in help-packs, which might be bundeled with the installer or provided as separate packages. They are supposed to be installed by a user to provide localized help. Both HTML-based help types are displayed in a browser, while the XML help uses an internal viewer component.
The XML help is the only one supported in extensions.
--with-help: selects the help type to build --with-omindex: prepares the online help for a Xapian Omega based search index --disable-xmlhelp: removes support for the XML help --with-helppack-integration: includes the help-packs in the installer
Also see configure --help.
This type was bundeled per-default until LibreOffice 6.0.
This help output is generated by using two tools: HelpIndexer and HelpLinker. It uses an internal viewer component. Extensions still use this help type to ship their help. This output is originally based on JavaDoc.
The main support for this help type is in the following directories:
Most code is "marked" by HAVE_FEATURE_XMLHELP precompiler blocks or conditioned by the XMLHELP flag in the $BUILD_TYPE variable.
Interestingly the HelpIndexer and HelpLinker are used by gbuild to build the help inside bundeled extensions, but both are not part of the LibreOffice SDK.
This type is bundeled per-default since LibreOffice 6.0 and displayed in a browser.
This help is the external one, currently provided by help.libreoffice.org. It differs from the bundeled HTML help in three main aspects:
It is opened in a browser.