diff --git a/includes/data-stores/class-wc-product-data-store-cpt.php b/includes/data-stores/class-wc-product-data-store-cpt.php
index aefeee39360..e87fc25f1e5 100644
--- a/includes/data-stores/class-wc-product-data-store-cpt.php
+++ b/includes/data-stores/class-wc-product-data-store-cpt.php
@@ -572,8 +572,22 @@ class WC_Product_Data_Store_CPT extends WC_Data_Store_WP implements WC_Object_Da
 				case 'stock_quantity':
 					// Fire actions to let 3rd parties know the stock is about to be changed.
 					if ( $product->is_type( 'variation' ) ) {
+						/**
+						* Action to signal that the value of 'stock_quantity' for a variation is about to change.
+						*
+						* @since 4.9
+						*
+						* @param int $product The variation whose stock is about to change.
+						*/
 						do_action( 'woocommerce_variation_before_set_stock', $product );
 					} else {
+						/**
+						* Action to signal that the value of 'stock_quantity' for a product is about to change.
+						*
+						* @since 4.9
+						*
+						* @param int $product The product whose stock is about to change.
+						*/
 						do_action( 'woocommerce_product_before_set_stock', $product );
 					}
 					break;