the list of principals included in the ssh host certificate. This is the list of hostnames and/or IP addresses that are authorized to serve SSH traffic with this certificate. Dangerously, if no principals are specified, this certificate is considered valid for all hosts.
the signed SSH certificate in OpenSSH Authorized Keys format. this value should be placed in a -cert.pub certificate file on disk that should be referenced in your sshd_config configuration file with a HostCertificate directive