How to Customize “WordPress > Error” Text in Titlebar?

Changing interface string is often done using gettext translation filter, but I was in the mood for something different so creatively mangled die handler to achieve it:

add_filter( 'wp_die_handler', function () {

    if ( false !== strpos( $_SERVER['SCRIPT_NAME'], 'wp-comments-post.php' ) ) {
        return function ( $message, $title, $args ) {
            _default_wp_die_handler( $message, 'Our Custom Title', $args );
        };
    }

    return '_default_wp_die_handler';
} );