nope, it just says
The application “A Heart of Butterblue 1.2 Mac” can’t be opened.
and then another pop comes up
Safari can’t open the file “A Heart of Butterblue 1.2 Mac” because no available application can open it.
Ah, okay! I got a friend to take a look at it on their Mac (Mac Monterey) and it appears to be this issue: https://superuser.com/questions/1345755/how-to-fix-the-application-cant-be-opene...
You can try the steps in that post!
It looks like something about version 1.2 doesn't play nice with some Mac OS and will get flagged. My friend did tell me they didn't have this issue at all with build 1.1 though. I've also unhidden the Mac 1.1 build if you still couldn't get the above steps to resolve the issue. (Just a caveat that there are some bugs in this version)
Hope that helps!