Specifies an optional Base64-encoded certificate that corresponds with the private key for TLS-based liveness tests (HTTPS, SMTPS, POPS, and TCPS). When the liveness test doesn't contain sslClientCertificate and sslClientPrivateKey values, use this and the defaultSslClientPrivateKey object fields to generate a certificate. In this case, use a separate, throwaway private key when generating a certificate or certificate signing request (CSR). You shouldn't use this key for any other purpose. See also defaultSslClientPrivateKey within this object.