WordPress at Your Fingertips
action is not described

woocommerce_checkout_before_customer_details action-hook . WC 1.0

Usage

add_action( 'woocommerce_checkout_before_customer_details', 'action_function_name_864' );
function action_function_name_864(){
	// action...
}

Where the hook is called

In file: /templates/checkout/form-checkout.php
woocommerce_checkout_before_customer_details
woocommerce/templates/checkout/form-checkout.php 36
<?php do_action( 'woocommerce_checkout_before_customer_details' ); ?>

Where in WP core the hook is used WooCommerce

woocommerce/includes/wc-template-hooks.php 220
add_action( 'woocommerce_checkout_before_customer_details', 'wc_get_pay_buttons', 30 );