code: protected void addExtraDocsBindings(final DocWorkUnit currentWorkUnit)
      {
          final List<Map<String, Object>> extraDocsData = new ArrayList<Map<String, Object>>();
  
          // add in all of the explicitly related extradocs items
          for (final Class<?> extraDocClass : currentWorkUnit.getDocumentedFeature().extraDocs()) {
              final DocWorkUnit otherUnit = getDoclet().findWorkUnitForClass(extraDocClass);
              if (otherUnit != null) {
                  extraDocsData.add(
                          new HashMap<String, Object>() {
                              static final long serialVersionUID = 0L;
                              {
                                  put("name", otherUnit.getName());
                                  put("filename", otherUnit.getTargetFileName());
                              }
                          });
              } else {
                  final String msg = String.format(
                          "An \"extradocs\" value (%s) was specified for (%s), but the target was not included in the " +
                          "source list for this javadoc run, or the target has no documentation.",
                          extraDocClass,
                          currentWorkUnit.getName()
                  );
                  throw new DocException(msg);
              }
          }
          currentWorkUnit.setProperty("extradocs", extraDocsData);
      }
docs: Add bindings describing related capabilities to currentWorkUnit