let _MailserverSecrets = {
  relay_user    | String
                | doc "SMTP relay authentication username",
  relay_password | String
                 | doc "SMTP relay authentication password",
  admin_email   | String
                | doc "Postmaster / admin mailbox address",
  admin_pass    | String
                | doc "Admin mailbox password",
} in

{
  MailserverSecrets = _MailserverSecrets,
}