src/Controller/Component/ListFilterComponent.php
protected function _getPersistendStorageKey($key)
    {
        if (!isset($this->config[$key]['namespace'])) {
            $namespace = 'ListFilter';
        } else {
            $namespace = $this->config[$key]['namespace'];
        }
        $sessionKey = [
            'namespace' => $namespace,
            'plugin' => 'App',
            'controller' => $this->_controller->request->controller,
            'action' => $this->_controller->request->action
        ];
        if (!empty($this->_controller->request->plugin)) {
            $sessionKey['plugin'] = $this->_controller->request->plugin;
        }
        $sessionKey = implode('.', $sessionKey);

        return $sessionKey;
    }
protected function _getPersistendStorageKey($key)
    {
        if (!isset($this->config[$key]['namespace'])) {
            $namespace = 'ListFilter';
        } else {
            $namespace = $this->config[$key]['namespace'];
        }
        $sessionKey = [
            'namespace' => $namespace,
            'plugin' => 'App',
            'controller' => $this->_controller->request->controller,
            'action' => $this->_controller->request->action
        ];
        if (!empty($this->_controller->request->plugin)) {
            $sessionKey['plugin'] = $this->_controller->request->plugin;
        }
        $sessionKey = implode('.', $sessionKey);

        return $sessionKey;
    }
Get persistent storage key for ListFilter form handling

@param  string  $key  The storage key defined in config
@return array