chromium/chromeos/components/test/data/onc/policy/policy_vpn.onc

{
  "NetworkConfigurations":[
    {
      "GUID":"{a3860e83-f03d-4cb1-bafa-b22c9e746950}",
      "Name":"my vpn",
      "Type":"VPN",
      "VPN":{
        "AutoConnect":false,
        "Host":"vpn.my.domain.com",
        "OpenVPN":{
          "OTP":"ignored OTP",
          "Password":"some password",
          "Port":443,
          "Proto":"udp",
          "SaveCredentials":false,
          "UserAuthenticationType":"Password",
          "Username":"abc ${LOGIN_EMAIL} def"
        },
        "Type":"OpenVPN"
      }
    }
  ],
  "Type":"UnencryptedConfiguration"
}