chromeos/test/data/network/shill_l2tpipsec_clientcert.json

{
   "GUID": "guid",
   "L2TPIPsec.Password": "some password",
   "L2TPIPsec.User": "some username",
   "Name": "MyL2TPVPN",
   "Provider.Host": "some.host.org",
   "Provider.Type": "l2tpipsec",
   "SaveCredentials": true,
   "Type": "vpn",
}