code: public void addSharedSite() {
  
          String shared = OpenCms.getSiteManager().getSharedFolder();
          if (shared.endsWith("/")) {
              // IMPORTANT: remove last "/".
              // Otherwise the version without slash will be added as well when you are in the shared folder currently.
              shared = shared.substring(0, shared.length() - 1);
          }
          if ((shared != null) && m_cms.existsResource(shared, CmsResourceFilter.ONLY_VISIBLE_NO_DELETED)) {
              addOption(
                  Type.shared,
                  shared,
                  org.opencms.workplace.Messages.get().getBundle(
                      OpenCms.getWorkplaceManager().getWorkplaceLocale(m_cms)).key(
                          org.opencms.workplace.Messages.GUI_SHARED_TITLE_0));
          }
      }
docs: Adds the shared folder.<p>