Are these the same thing?
When I click on Google links to the Dubrovnik card, my firewall is telling me that it's not safe.
When I enter dubrovnikcard.com in the search bar, it redirects me to https://www.dubrovnikpass.com/
Trust your browser regarding safety. However, it appears that the card and the pass may be one and the same. Here is a link that explains the card in more detail than the official site. It is for information only, not for purchasing the card/pass.
https://walkindubrovnik.com/dubrovnik-card/
Also, there is a museum pass that is different from the above.