You will need to do the following to try xr immersive mode with your application.

  1. Use https. The examples use webpack dev-server which supports serving https. 
      module.exports = {
 //...
 devServer: {
   https: true
 }
  };

    See Webpack dev-server for more details.

  2. Due to CORS restrictions, you can only connect via localhost or 127.0.0.1. You will need to connect your webxr device to your dev machine and enable port forwarding in the DevTools devices section of chrome. See Chrome Remote Debugging

  3. Add allow='xr-spatial-tracking' to the iframe that loads the showcase.html file of the bundle.