I had to find an application to test, so I downloaded the kitty terminal emulator for macOS which was just an executable.

I tried to execute it from the shell ./kitten-darwin-arm64 and it gave me an option to cancel or move to bin. I went to system settings -> privacy & security -> and told it to allow kitten-darwin-arm64. I then rerun ./kitten-darwin-arm64 and it now had the option to "Open Anyway".

So in 15.2 it is still possible to execute software by unidentified developers.