The online manual consists of a large set of tools to examine different aspects of the XPCE/Prolog environment and to navigate through the available material from different view-points.
<home>/prolog/demo, where <home> refers to the XPCE installation directory, which may be obtained using
1 ?- get(@pce, home, Home). Home = '/usr/local/lib/pl-4.0.0/xpce'
Note that the DemoBrowser allows to view the sources of the main file of a demo application immediately. Also consider using the VisualHierarchy and ClassBrowser to analyse the structure of the demo programs.