Context - This is a proposal from Google based on our experience consuming schema.org Offer markup and working with similar data from online merchants. If it were accepted, it would make it easier for us and others to understand delivery routes for products sold online.

Proposal - Schema.org supports the specification of shipping destinations (through the shippingDestination property) where an online merchant delivers ordered products to. However, Schema.org currently does not support shipping origins, where merchants ship the product from. Often a product's shipping source is relevant information for consumers, so propose to add a new shippingOrigin property of type DefinedRegion for use on type OfferShippingDetails.

Alternatives - Instead of adding the shipping origin under OfferShippingDetails we could consider adding it under Offer directly to avoid having to repeat the origin for every separate OfferShippingDetails instance. However, the flexibility of having different origins depending on the destination is useful, especially for retailers with multiple fulfillment centers and warehouses.