WordPress at a glance
action is not described

login_init action-hook . WP 3.2.0

Fires when the login form is initialized.

Usage

add_action( 'login_init', 'action_function_name_7472' );
function action_function_name_7472(){
	// action...
}

Changelog

Since 3.2.0 Introduced.

Where the hook is called

In file: /wp-login.php
login_init
wp-login.php 548
do_action( 'login_init' );

Where in WP core the hook is used WordPress

wp-login.php 43
add_action( 'login_init', 'wp_admin_headers' );
wp-login.php 320
add_action( 'login_init', 'send_frame_options_header', 10, 0 );