Go 1.25 disabled SHA-1 signature algorithms in TLS 1.2 according to RFC 9155.
The default can be reverted using the `tlssha1=1` setting.

Go 1.25 switched to SHA-256 to fill in missing SubjectKeyId in
crypto/x509.CreateCertificate. The setting `x509sha256skid=0` reverts to SHA-1.

Go 1.25 corrected the semantics of contention reports for runtime-internal locks,

		} else {
			template.DNSNames = append(template.DNSNames, h)
		}
	}

	template.IsCA = true
	template.KeyUsage |= x509.KeyUsageCertSign

	derBytes, err := x509.CreateCertificate(crand.Reader, &template, &template, publicKey(priv), priv)
	if err != nil {
		return nil, nil, fmt.Errorf("Failed to create certificate: %w", err)
	}

	certOut := bytes.NewBuffer([]byte{})

pkg crypto/x509, const TooManyIntermediates InvalidReason
pkg crypto/x509, const UnknownPublicKeyAlgorithm PublicKeyAlgorithm
pkg crypto/x509, const UnknownSignatureAlgorithm SignatureAlgorithm
pkg crypto/x509, func CreateCertificate(io.Reader, *Certificate, *Certificate, interface{}, interface{}) ([]uint8, error)
pkg crypto/x509, func MarshalPKCS1PrivateKey(*rsa.PrivateKey) []uint8
pkg crypto/x509, func MarshalPKIXPublicKey(interface{}) ([]uint8, error)