WordPress at a glance
action is not described

login_init action-hook . WP 3.2.0

Fires when the login form is initialized.


add_action( 'login_init', 'action_function_name_4966' );
function action_function_name_4966(){
	// action...

Where the hook is called

In file: /wp-login.php
wp-login.php 478
do_action( 'login_init' );

Where the hook is used (in WP core)

wp-admin/includes/admin-filters.php 42
add_action( 'login_init', 'wp_admin_headers' );
wp-includes/default-filters.php 318
add_action( 'login_init', 'send_frame_options_header', 10, 0 );