Class yii\debug\actions\db\ExplainAction

                public function run($seq, $tag)
{
    $this->controller->loadData($tag);
    $timings = $this->panel->calculateTimings();
    if (!isset($timings[$seq])) {
        throw new HttpException(404, 'Log message not found.');
    }
    $query = $timings[$seq]['info'];
    $results = $this->panel->getDb()->createCommand('EXPLAIN ' . $query)->queryAll();
    $output[] = '<table class="table"><thead><tr>' . implode(array_map(function($key) {
        return '<th>' . $key . '</th>';
    }, array_keys($results[0]))) . '</tr></thead><tbody>';
    foreach ($results as $result) {
        $output[] = '<tr>' . implode(array_map(function($value) {
            return '<td>' . (empty($value) ? 'NULL' : htmlspecialchars($value)) . '</td>';
        }, $result)) . '</tr>';
    }
    $output[] = '</tbody></table>';
    return implode($output);
}