Merge pull request AdobeDocs#294 from ankitpatel2931/patch-1

Verified that `AC-View-ID` is required.  Added AC-Source-Locale header back since it is still in use.

Author: meker12

src/pages/optimizer/merchandising-services/using-the-api.md

@@ -66,7 +66,8 @@ When making requests to the storefront API, you must include required HTTP heade
 
 | Header name| Description
 | --- | ---
-|`AC-View-ID` | Optional. The unique ID assigned to catalog view that products will be sold through. For example, in the automotive industry, the catalog view could be dealers. In the manufacturing industry, the view could be a manufacturing location for suppliers. You can view the list of available catalog views and find the viewID from the [Adobe Commerce Optimizer UI](https://experienceleague.adobe.com/en/docs/commerce/optimizer/setup/catalog-view).|
+|`AC-View-ID` | Required. The unique ID assigned to the catalog view that products will be sold through. For example, in the automotive industry, the catalog view could be dealers. In the manufacturing industry, the view could be a manufacturing location for suppliers. You can view the list of available catalog views and find the viewID from the [Adobe Commerce Optimizer UI](https://experienceleague.adobe.com/en/docs/commerce/optimizer/setup/catalog-view).|
+`AC-Source-Locale`: | Required. The catalog source locale (language or geography) to filter products for display or update, for example `en_US`. See the catalog view configuration in the [Adobe Commerce Optimizer UI](https://experienceleague.adobe.com/en/docs/commerce/optimizer/catalog/channels) to determine the correct value.|
 `AC-Policy-{*}` | Optional. The trigger name configured for a policy that sets data access filters to restrict product access based on request attributes and context. Examples include POS physical stores, marketplaces, or advertisement pipelines like Google, Meta, or Instagram. You can view the list of available policies and associated ids from the [Adobe Commerce Optimizer UI](https://experienceleague.adobe.com/en/docs/commerce/optimizer/catalog/policies). You can specify multiple policy headers per request. Example: `AC-Policy-Brand`.
 `AC-Price-Book-ID` | Optional. Defines how prices are calculated for a specific catalog view. Supply this value if the merchant uses price books to calculate product pricing. If you do not include the Price Book ID, Merchandising Services provides a default price book `main` with currency in US dollars. See the Catalog View configuration for a list of price books available for use with the specifed Catalog View.