By default, Commerce includes messages used by the Gift with Purchase promotion feature. To enable messages related to this feature, set the following property to true:

PricingTools.sendGWPMessages

By default, Commerce includes a GiftWithPurchaseMessages message group that is used to send messages for that feature.

The default slot for Gift with Purchase messages is /atg/commerce/pricing/NoCleanBeforePricingSlot. Messages are removed from this slot as they are retrieved.