It is a trailer; see the source code, line 100: message = f"{base_message}\n\ngit-prime Nonce: {attempt}" I'm not sure whether that's a valid head

It is a trailer; see the source code, line 100: message = f"{base_message}\n\ngit-prime Nonce: {attempt}" I'm not sure whether that's a valid header name, with the space and all, but I remarked on that in another comment already.