docs: public void checkOfflineProject(CmsDbContext dbc) throws CmsVfsException {
  
          if (dbc.currentProject().isOnlineProject()) {
              throw new CmsVfsException(
                  org.opencms.file.Messages.get().container(
                      org.opencms.file.Messages.ERR_NOT_ALLOWED_IN_ONLINE_PROJECT_0));
          }
      }