login_header action-hook . WP 4.6.0
Fires in the login page header after the body tag is opened.
Usage
add_action( 'login_header', 'action_function_name_6826' );
function action_function_name_6826(){
// action...
}Where the hook is called
login_header
wp-login.php 196
do_action( 'login_header' );