systemLabels property

Output only. Values for predefined system metadata labels. System labels are a kind of metadata extracted by Google, including "machine_image", "vpc", "subnet_id", "security_group", "name", etc. System label values can be only strings, Boolean values, or a list of strings. For example:

{ "name": "my-test-instance",
  "security_group": ["a", "b", "c"],
  "spot_instance": false }