return nil, ErrTLSUnexpectedData(nil).Msgf("Could not read PEM block from file %s", certFile)
		}

		var x509Cert *x509.Certificate
		if x509Cert, err = x509.ParseCertificate(pemBlock.Bytes); err != nil {
			return nil, ErrTLSUnexpectedData(nil).Msgf("Failed to parse `%s`: %s", certFile, err.Error())
		}

		x509Certs = append(x509Certs, x509Cert)
	}

	if len(x509Certs) == 0 {

Go 1.23 changed the behavior of
[crypto/x509.ParseCertificate](/pkg/crypto/x509/#ParseCertificate) to reject
serial numbers that are negative. This change can be reverted with
the [`x509negativeserial` setting](/pkg/crypto/x509/#ParseCertificate).

Go 1.23 re-enabled support in html/template for ECMAScript 6 template literals by default.