wp_admin_bar_header()

Source

File: wp-includes/admin-bar.php

function wp_admin_bar_header() {
	$type_attr = current_theme_supports( 'html5', 'style' ) ? '' : ' type="text/css"';
	?>
<style<?php echo $type_attr; ?> media="print">#wpadminbar { display:none; }</style>
	<?php
}