 update_quantity($product_id, $quantity) - Change item quantity clear_cart() - Empty entire cart (after order) get_cart_count() - Get total item count set_coupon($coupon_data) - Apply discount coupon get_coupon() - Retrieve applied coupon clear_coupon() - Remove applied coupon File: /includes/class-cart-widget.php Purpose: Display mini cart with item count badge Registering: Extends WP_Widget class Location: Appearance > Widgets > Shopping Cart Setting Group: agency_pulse_shopping_cart_settings Sanitization: absint() for page IDs, boolean sanitization for checkboxes Tab: "Products Plugin" tab on Invoices > Settings Priority: 30 (places after default tabs)