From the Enriched Catalog Designs homepage you will see that each one your designs has a status indicator that informs you how the feed URL is currently being used.
Design Status Details:
Under the name of the designs you will see a link to the output feed that the design is currently linked to.
If the color indicator is green the design has been rendered and currently exists in the linked output feed.
If the color indicator is blue the design has been linked to the output feed but you still need to publish the updates to the output feed in order to render the design into the output.
Any designs that are not linked to an output feed will show "draft" instead of linking to an output.
Published feed designs are always separated from the other feed designs at the top of the page.