This is the administrator-assigned name for the configuration for fetching and importing a trust certificate used to secure the VMM connection. It's the human-friendly label an admin actually types into the UCS Manager GUI or CLI to refer to that keyring, as opposed to the Dn or Guid which are needed for programmatic lookups but aren't something a person would type from memory. A value like 'vcenter-trust-ring' would be exactly the kind of name an admin chooses so the object is recognizable in a list without opening it.