WordPress at a glance
filter is not described

woocommerce_email_order_item_quantity filter-hook . WC 1.0

Usage

add_filter( 'woocommerce_email_order_item_quantity', 'filter_function_name_1549', 10, 2 );
function filter_function_name_1549( $qty_display, $item ){
	// filter...

	return $qty_display;
}
$qty_display
-
$item
-

Where the hook is called

In file: /templates/emails/email-order-items.php
woocommerce_email_order_item_quantity
woocommerce/templates/emails/email-order-items.php 82
echo wp_kses_post( apply_filters( 'woocommerce_email_order_item_quantity', $qty_display, $item ) );
woocommerce/templates/emails/plain/email-order-items.php 38
echo ' X ' . apply_filters( 'woocommerce_email_order_item_quantity', $item->get_quantity(), $item );
woocommerce/includes/class-wc-structured-data.php 475
'value' => apply_filters( 'woocommerce_email_order_item_quantity', $item->get_quantity(), $item ),

Where in WP core the hook is used WooCommerce

Usage not found.