// PROMOBILE_SEO_PRODUCT_META_PANEL_V1
AddEventHandler("main", "OnEpilog", "promobileSeoProductMetaFromPanelV1", 1200);
function promobileSeoProductMetaFromPanelV1()
{
    global $APPLICATION;
    if ((defined('ADMIN_SECTION') && ADMIN_SECTION === true) || (defined('ERROR_404') && ERROR_404 === 'Y')) return;
    $path = parse_url(isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '/', PHP_URL_PATH);
    if (!$path || strpos($path, '/catalog/') !== 0 || substr($path, -1) !== '/' || !\CModule::IncludeModule('iblock')) return;
    $code = basename(rtrim($path, '/'));
    if ($code === '' || $code === 'catalog') return;
    $elementId = 0;
    $query = \CIBlockElement::GetList(array(), array('IBLOCK_ID' => 26, 'ACTIVE' => 'Y', '=CODE' => $code), false, false, array('ID', 'DETAIL_PAGE_URL'));
    while ($element = $query->GetNext()) {
        if (parse_url((string)$element['DETAIL_PAGE_URL'], PHP_URL_PATH) === $path) { $elementId = (int)$element['ID']; break; }
    }
    if ($elementId <= 0) return;
    $values = (new \Bitrix\Iblock\InheritedProperty\ElementValues(26, $elementId))->getValues();
    if (!empty($values['ELEMENT_META_TITLE'])) $APPLICATION->SetPageProperty('title', trim((string)$values['ELEMENT_META_TITLE']));
    if (!empty($values['ELEMENT_META_DESCRIPTION'])) $APPLICATION->SetPageProperty('description', trim((string)$values['ELEMENT_META_DESCRIPTION']));
    if (!empty($values['ELEMENT_PAGE_TITLE'])) $APPLICATION->SetTitle(trim((string)$values['ELEMENT_PAGE_TITLE']));
}
<pre>[RuntimeException] 
Could not start session because headers have already been sent. &quot;/home/users/j/j2738487/domains/promobile.pro/bitrix/php_interface/init.php&quot;:1159. (0)
/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/lib/Session/Session.php:143
#0: Bitrix\Main\Session\Session-&gt;start
	/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/lib/Session/KernelSessionProxy.php:47
#1: Bitrix\Main\Session\KernelSessionProxy-&gt;start
	/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/include.php:151
#2: require_once(string)
	/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/include/prolog_before.php:19
#3: require_once(string)
	/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/include/prolog.php:10
#4: require_once(string)
	/home/users/j/j2738487/domains/promobile.pro/bitrix/header.php:2
#5: require(string)
	/home/users/j/j2738487/domains/promobile.pro/catalog/index.php:1
#6: include_once(string)
	/home/users/j/j2738487/domains/promobile.pro/bitrix/modules/main/include/urlrewrite.php:128
#7: include_once(string)
	/home/users/j/j2738487/domains/promobile.pro/bitrix/urlrewrite.php:2
----------
</pre>