WordPress at a glance
action is not described

woocommerce_before_shop_loop_item action-hook . WC 1.0

Hook: woocommerce_before_shop_loop_item.

Usage

add_action( 'woocommerce_before_shop_loop_item', 'action_function_name_5654' );
function action_function_name_5654(){
	// action...
}

Where the hook is called

In file: /templates/content-product.php
woocommerce_before_shop_loop_item
woocommerce/templates/content-product.php 34
do_action( 'woocommerce_before_shop_loop_item' );

Where in WP core the hook is used WooCommerce

woocommerce/includes/wc-template-hooks.php 94
add_action( 'woocommerce_before_shop_loop_item', 'woocommerce_template_loop_product_link_open', 10 );