wp_admin_headers() │ WP 4.9.0

Sends a referrer policy header so referrers are not sent externally from administration screens.

Hooks from the function

Returns

null. Nothing (null).

Usage

wp_admin_headers();

Changelog

Since 4.9.0 Introduced.
Since 6.8.0 This function was moved from wp-admin/includes/misc.php to wp-includes/functions.php.

wp_admin_headers() code WP 7.0

wp-includes/functions.php 
function wp_admin_headers() {
	$policy = 'strict-origin-when-cross-origin';

	/**
	 * Filters the admin referrer policy header value.
	 *
	 * @since 4.9.0
	 * @since 4.9.5 The default value was changed to 'strict-origin-when-cross-origin'.
	 *
	 * @link https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Referrer-Policy
	 *
	 * @param string $policy The admin referrer policy header value. Default 'strict-origin-when-cross-origin'.
	 */
	$policy = apply_filters( 'admin_referrer_policy', $policy );

	header( sprintf( 'Referrer-Policy: %s', $policy ) );
}