chromium/chromeos/components/test/data/onc/vpn_ipsec_clientcert_pkcs11.onc

{
    "GUID": "{84391467-dd8b-4c66-9b52-860583038351}",
    "Name": "TestIpsecVPN",
    "ProxySettings": {
        "Type": "Direct"
    },
    "Type": "VPN",
    "VPN": {
        "Host": "terminus.muc",
        "IPsec": {
            "AuthenticatioType": "Cert",
            "ClientCertPKCS11Id": "1:123456abcdef",
            "ClientCertType": "PKCS11Id",
        },
        "L2TP": {
            "Password": "some password",
            "SaveCredentials": true,
            "Username": "hans"
        },
        "Type": "L2TP-IPsec"
    }
}