Anyone who opens this link sees exactly what you see. The setup is stored inside the link itself.
There are no accounts, and this tool doesn't collect your name, email or anything else about you.
Your upgrade levels, targets and saved builds are stored only in your own browser (local storage). They're never sent anywhere. Clearing your browser's site data erases them.
Share links carry the build inside the link itself. Anyone you send a link to can see that build.