chromium/chromeos/components/test/data/onc/toplevel_wifi_open.onc

// Test ONC file for importing an open network.
{
  "NetworkConfigurations": [
    {
      "GUID": "{485d6076-dd44-6b6d-69787465725f5040}",
      "IPAddressConfigType": "DHCP",
      "Type": "WiFi",
      "Name": "My WiFi Network",
      "WiFi": {
        "SSID": "ssid-none",
        "Security": "None"
      }
    }
  ],
  "Certificates": [],
  "Type": "UnencryptedConfiguration"
}