WordPress at a glance
function is not described

do_favicon() WP 5.4.0

Display the favicon.ico file content.

Hooks from the function
Return

Null. Nothing.

Usage

do_favicon();

Changelog

Since 5.4.0 Introduced.

Code of do favicon: wp-includes/functions.php WP 5.4.2

<?php
function do_favicon() {
	/**
	 * Fires when serving the favicon.ico file.
	 *
	 * @since 5.4.0
	 */
	do_action( 'do_faviconico' );

	wp_redirect( get_site_icon_url( 32, includes_url( 'images/w-logo-blue-white-bg.png' ) ) );
	exit;
}