WordPress at a glance
action is not described

admin_xml_ns action-hook . WP 2.2.0

Fires inside the HTML tag in the admin header.

Usage

add_action( 'admin_xml_ns', 'action_function_name_1818' );
function action_function_name_1818(){
	// action...
}

Changelog

Since 2.2.0 Introduced.

Where the hook is called

_wp_admin_html_begin()
admin_xml_ns
wp-admin/includes/template.php 2435
do_action( 'admin_xml_ns' );
wp-admin/includes/template.php 2445
do_action( 'admin_xml_ns' );

Where in WP core the hook is used

Usage not found!