Downloaded both beta and default versions, but neither worked. Same version number, so go figure.
Chisel through a layer cake of thousand-year-old civilizations. · By
Seems it's a permissions issue, needs to be explicitly allowed since it isn't signed on newer macos: https://itch.io/t/1849862/macos-coq-is-brokendamaged-solution
You can probably also "allow apps downloaded from", as described here: https://appletoolbox.com/app-is-damaged-cannot-be-opened-mac/