mdm\upload\UploadBehavior::events PHP Method

    public function events()
    {
        $event = [];
        if ($this->autoSave) {
            $event[BaseActiveRecord::EVENT_BEFORE_INSERT] = 'beforeSave';
            $event[BaseActiveRecord::EVENT_BEFORE_UPDATE] = 'beforeSave';
        }
        if ($this->autoDelete && $this->savedAttribute !== null) {
            $event[BaseActiveRecord::EVENT_BEFORE_DELETE] = 'beforeDelete';
        }
        return $event;
    }