docs: public String getSiteRoot(String rootPath) {
  
          // add a trailing slash, because the path may be the path of a site root itself
          if (!rootPath.endsWith("/")) {
              rootPath = rootPath + "/";
          }
          // most sites will be below the "/sites/" folder,
          CmsSite site = lookupSitesFolder(rootPath);
          if (site != null) {
              return site.getSiteRoot();
          }
          // look through all folders that are not below "/sites/"
          return lookupAdditionalSite(rootPath);
      }