This operation lists all versions of a service hostname set. You can modify a version until it's activated. Once you activate a version, you need to create a new one to edit its settings. Service hostnames are fully qualified domain names (FQDN) that resolve requests from a client to the Akamai edge server and identify traffic rules. You group hostnames into sets to centrally manage shared settings, including certificates, edge hostname assignments, and TLS, for reuse across environments.