Are the votes really anonymous?
Absolutely! It's actually a strong requirement I don't want to debate on. The AI assistants never see who voted what either. As a scrum master, you should guess who voted what anyway. The goal of this tool is to leverage the data via a relevant chart to speak to your management.
The local storage is used to avoid voting twice. Only the survey UUID is stored, not even the actual vote neither the comment.
Completing the local storage topic: the cookies. One cookie is used to store the authentication token when you are logged in. Which applies to scrum masters only. Nevertheless, scrum masters can anonymously vote too! Another cookie is used to store the language you select when clicking on the footer.