Can anyone tell me, does disabling ‘Development Build’ in Build Settings actually remove all Debug statements and prevent them from running, or does it simply prevent them from appearing?
Yes and no. Assert() will become a no-op without a special compiler flag. Log() will continue to write output to the log files, though I think there’s a setting tucked away somewhere in your Player options to disable that, but it can be quite handy. Things like DrawRay() and DrawLine() almost certainly become no-ops as well.