You can view the reserved stock in the Product details under Stock in the Overview section.
It is made up of all orders whose order status is not Cancelled or Completed and whose delivery status is not Cancelled or Shipped. This also applies to custom order and delivery statuses. When you click the Reserved stock field, the Orders tab opens with the corresponding filters, so you can see all relevant orders. In the Orders tab, you can also narrow down the list directly via the statuses: Clicking a label in the Delivery status or Payment status column shows only orders with that status, and a second click removes the filter again.
Reservations apply globally to the product, not per warehouse.
When is stock booked out?
Changing the order or delivery status does not book out any stock. Pickware is decoupled from the Shopware status here: The status only controls whether stock is reserved. Stock is only booked out in these ways:
In the Shopware Admin via Ship order on the order
In the WMS App via Picked → Mark as shipped
Via bulk edit for multiple orders
Creating a shipping label, for example from DHL, does not book out any stock either.
How do I release a reservation?
A reservation ends when you set the order status to Cancelled or Completed. A modified payment status alone is not enough.
A typical case: The delivery status is set to Returned, but the order status is still Open. In that case, the stock remains reserved until you complete or cancel the order.
Tip: You can have orders with failed payments cancelled automatically. To do so, create a flow under Settings → Automation → Flow Builder that sets the order status to Cancelled when the payment status is Failed.