Xcode.app includes a digital signature, which can be checked with `codesign`. As all OS X comes bundled with Apple's root certificate, one can check for the val

Xcode.app includes a digital signature, which can be checked with `codesign`. As all OS X comes bundled with Apple's root certificate, one can check for the validity of that application by oneself without any additional trusted source. Or if the developers never disable GateKeeper and read the warning, they will know that the application is not genuine.