WordPress at a glance
function is not described

wp_admin_bar_header() WP 3.1.0

Style and scripts for the admin bar.

No Hooks.

Return

null. Nothing.

Usage

wp_admin_bar_header();

Changelog

Since 3.1.0 Introduced.

Code of wp_admin_bar_header() WP 5.7.2

<?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
}