The 16.5.0 package released to unpkg currently has the production/profiling variant present for cjs builds but there is no equivalent for umd builds. 

i.e. There is the file https://unpkg.com/react@16.5.0/cjs/react.profiling.min.js but there is no https://unpkg.com/react@16.5.0/umd/react.profiling.min.js

It would be great if a future release had the profiling variant packaged as umd as well.

Also thanks for the awesome framework!
if (!existsSync('build/node_modules')) {
    
    return;
  }
  const builtPackageFolders = readdirSync('build/node_modules').filter(
    dir => dir.charAt(0) !== '.'
  );
  await Promise.all(builtPackageFolders.map(prepareNpmPackage));
}
module.exports = {
  copyAllShims,
  getPackageName,
  getBundleOutputPaths,
  prepareNpmPackages,
};