If the certificate chain has been built and is of status gcr_certificate_chain_anchored, then this will return the anchor certificate that was found.
This is not necessarily a root certificate authority. If an intermediate certificate authority in the chain was found to be anchored, then that certificate will be returned.
If an anchor is returned it does not mean that the certificate chain has been verified, but merely that an anchor has been found.
the anchor certificate, or null if not anchored.