Running example on http://localhost:8080 for Cookieless embed
Results are the same when domain http://localhost:8080 is not added to Allow List. The following modal will display if domain isn't added to allow list when session reference token or short-lived tokens are about to expire.
As shown on screenshot, the state Loading... won't be updated to Done even though the dashboard finished loading. Also, the Resume session button doesn't do anything in this case.

If adding to domain allow list is required, please add it in the README's Embeded Javascript Events section to indicate that without allowing the domain, javascript events won't be received.