code: private function setLogDest($where = 'auto')
      {
          if ($where == 'auto') {
              $where = $this->data['groupPriorityStack']
                  ? 'summary'
                  : 'log';
          }
          if ($where == 'log') {
              $this->rootInstance->logRef = &$this->rootInstance->data['log'];
              $this->rootInstance->groupStackRef = &$this->rootInstance->data['groupStacks']['main'];
          } elseif ($where == 'alerts') {
              $this->rootInstance->logRef = &$this->rootInstance->data['alerts'];
          } else {
              $priority = \end($this->data['groupPriorityStack']);
              if (!isset($this->data['logSummary'][$priority])) {
                  $this->data['logSummary'][$priority] = array();
                  $this->data['groupStacks'][$priority] = array();
              }
              $this->rootInstance->logRef = &$this->rootInstance->data['logSummary'][$priority];
              $this->rootInstance->groupStackRef = &$this->rootInstance->data['groupStacks'][$priority];
          }
      }
docs: Set where appendLog appends to
  
  @param string $where ('auto'), 'alerts', log', or 'summary'
  
  @return void