This is a test trying to proof that useBuiltins does not work together with excluding core-js in babel-loader.
To reproduce, change the babel-loader rule in webpack.config.js to this:
{
test: /\.js$/,
exclude: /node_modules\/(core-js)/,
//include: [
// path.resolve(__dirname, 'node_modules/swiper'),
// path.resolve(__dirname, 'node_modules/dom3'),
//],
use: {
loader: 'babel-loader'
},
},