With HTML template like:

<script src="https://cdn.jsdelivr.net/npm/react@16.12.0/umd/react.production.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/react-dom@16.12.0/umd/react-dom.production.min.js"></script>

And a webpack config including:

{
    externals: {
        react: 'React',
        'react-dom': 'ReactDOM',
    }
}

This plugin fails to work.

I'd like to dive into it a little, but with little knowledge about webpack I'm not sure I can find any valuable ideas.