vscode debugger shows imported variables with an _ "underscore" prefix when using babel-node or node -r @babel/register

While debugging my ES6 babel-node project in vscode I see imported modules/objects include an _ "underscore" as a prefix. So as an example;

'./Foo.js'

export default class Foo{ constructor() {} }

'./index.js'

import Foo from './Foo';

in the debugger shows up as _Foo instead of Foo

if it matters my .babelrc is

{
  "presets": [
    "@babel/preset-env"
  ],
  "sourceMaps": "both",
}