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

{
    "GUID": "{64c4f86b-cf6a-4e4a-8eff-456def}",
    "Name": "OpenWrt",
    "ProxySettings": {
        "Manual": {
            "FTPProxy": {
                "Host": "192.168.2.1",
                "Port": 8889
            },
            "HTTPProxy": {
                "Host": "192.168.2.1",
                "Port": 8889
            },
            "SOCKS": {
                "Host": "192.168.2.1",
                "Port": 8889
            },
            "SecureHTTPProxy": {
                "Host": "192.168.2.1",
                "Port": 8889
            }
        },
        "Type": "Manual"
    },
    "Type": "WiFi",
    "WiFi": {
        "AutoConnect": true,
        "Frequency": 2412,
        "FrequencyList": [2412, 5180],
        "HexSSID": "4F70656E577274", // "OpenWrt"
        "HiddenSSID": false,
        "Passphrase": "some passphrase",
        "Security": "WPA-PSK"
    }
}