What is this piece of code for $content = str_replace($zzz, str_replace('href', 'rel="nofollow" href', $zzz), $content);?

Question

1C-Bitrix

Found the code in init.php. I know that it was made by some SEOs. But why I can't figure it out. Because of this function, the context menu does not work in the admin panel, in the data export interface.

AddEventHandler("main", "OnEndBufferContent", "AutoCloseLinksHandler");
function AutoCloseLinksHandler(&$content)
{
    $url = $_SERVER['HTTP_HOST'];
    
    preg_match_all("<a[^<>]*href=[\"|'](.*)[\"|'][^<>]*>", $content, $out_url);
    foreach ($out_url[0] as $val => $zzz) {
        if (preg_match('~http(s)?://~', $zzz) && !preg_match('~http(s)?://(www.)?' . $url . '~i', $zzz) && !preg_match('~rel="nofollow"~i', $zzz)) {
            $content = str_replace($zzz, str_replace('href', 'rel="nofollow" href', $zzz), $content);
        }
    }
}

Can you tell me what this code is for? Does he really need it?
And is it possible to exclude the processing of the admin panel in it?