If I try to load react-dom with RequireJS, I get an error: "Mismatched anonymous define()".
Looking at the react-dom from the 15.4.0 distribution (https://cdnjs.cloudflare.com/ajax/libs/react/15.4.0/react-dom.js), I notice that there seem to be two UMD wrappers at the top.
This is probably related to the change in the packaging structure (#7164 and #7168).
var version = grunt.config.data.pkg.version;
  var packageName = this.data.packageName || this.data.standalone;
  return (
    grunt.template.process(
      LICENSE_TEMPLATE,
      {data: {package: packageName, version: version}}
    ) +
    src
  );
}
function simpleBannerify(src) {
  var version = grunt.config.data.pkg.version;
  var packageName = this.data.packageName || this.data.standalone;
  return (
    grunt.template.process(
      SIMPLE_TEMPLATE,
      {data: {package: packageName, version: version}}
    ) +
    src
  );
}
function wrapperify(src) {
  return `
;(function(f) {
  // CommonJS
  if (typeof exports === "object" && typeof module !== "undefined") {
    f(require('react'));
  // RequireJS