WordPress at a glance
action is not described

woocommerce_cart_item_removed action-hook . WC 1.0

Usage

add_action( 'woocommerce_cart_item_removed', 'action_function_name_9579', 10, 2 );
function action_function_name_9579( $cart_item_key, $that ){
	// action...
}
$cart_item_key
-
$that
-

Where the hook is called

WC_Cart::remove_cart_item()
woocommerce_cart_item_removed
woocommerce/includes/class-wc-cart.php 1290
do_action( 'woocommerce_cart_item_removed', $cart_item_key, $this );

Where in WP core the hook is used WooCommerce

woocommerce/includes/class-wc-cart-session.php 56
add_action( 'woocommerce_cart_item_removed', array( $this, 'persistent_cart_update' ) );
woocommerce/includes/class-wc-cart.php 108
add_action( 'woocommerce_cart_item_removed', array( $this, 'calculate_totals' ), 20, 0 );