code: private List<IncludeAllPage> handleDepth0Page(List<IncludeAllPage> pages, FileResource resource, int maxDepth, Path defaultOutputPath) {
      
      boolean skipDepth0 = (boolean) resource.getMetadata().getRawMap().getOrDefault("ignore-depth-0-page", false);
  
      if (maxDepth == 0) {
        List<FileResource> files = new ArrayList<FileResource>();
        files.add(new FileResourcePlaceHolder(defaultOutputPath, configuration));
        if(!pages.isEmpty()) {
          files.addAll(pages.get(0).files);// we know that it has size 1
        }
        return Collections.singletonList(new IncludeAllPage(0, files));
        
      } else if (!skipDepth0) {
        pages.add(0, new IncludeAllPage(0, Collections.singletonList(new FileResourcePlaceHolder(defaultOutputPath, configuration))));
      }
  
      return pages;
    }
docs: /*
  It's a special case: depth 0 represent the page with the include-all directive. We let the user
  decide if he want to render it (default: yes). Additionally we handle the case where maxDepth
  is 0, we should transfer the IncludeAllPage object under the page that have the include-all
  directive.