// PROMOBILE_BRAND_NORMALIZATION_V1
AddEventHandler("main", "OnEndBufferContent", "promobileBrandNormalizationV1", 2000);
function promobileBrandNormalizationV1(&$content)
{
    if ((defined("ADMIN_SECTION") && ADMIN_SECTION === true) || !is_string($content) || $content === "") {
        return;
    }
    $content = str_replace(array("Promobile Butik", "PROMOBILE BUTIK"), "PROMOBILE Butik", $content);
    $content = preg_replace("/\\bPROMOBILE\\b(?!\\s+Butik)/u", "PROMOBILE Butik", $content);
}
<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;:976. (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>