WordPress at a glance
function is not described

send_nosniff_header() WP 3.0.0

Send a HTTP header to disable content type sniffing in browsers which support it.

No Hooks.

Return

Nothing (null).

Usage

send_nosniff_header();

Code of send nosniff header: wp-includes/functions.php VER 5.0.3

<?php
function send_nosniff_header() {
	@header( 'X-Content-Type-Options: nosniff' );
}