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

{
  "GlobalNetworkConfiguration": {
    "AllowAPNModification": true,
    "AllowCellularHotspot": true,
    "AllowCellularSimLock": true,
    "AllowOnlyPolicyCellularNetworks": false,
    "AllowOnlyPolicyNetworksToAutoconnect": false
  },
  "NetworkConfigurations": [
    {
      "GUID": "123",
      "Type": "Cellular",
      "Name": "Test Network",
      "Cellular": {
        "AllowRoaming": true,
        "AutoConnect": true
      }
    }
  ]
}