WordPress at a glance
function is not described

rsd_link() WP 2.0.0

Display the link to the Really Simple Discovery service endpoint.

No Hooks.

Return

Nothing (null).

Usage

rsd_link();

Code of rsd link: wp-includes/general-template.php WP 5.2.2

<?php
function rsd_link() {
	echo '<link rel="EditURI" type="application/rsd+xml" title="RSD" href="' . esc_url( site_url( 'xmlrpc.php?rsd', 'rpc' ) ) . '" />' . "\n";
}