Index: frontend/node_modules/react-dev-utils/InterpolateHtmlPlugin.js
===================================================================
--- frontend/node_modules/react-dev-utils/InterpolateHtmlPlugin.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/react-dev-utils/InterpolateHtmlPlugin.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// This webpack plugin lets us interpolate custom variables into `index.html`.
+// Usage: `new InterpolateHtmlPlugin(HtmlWebpackPlugin, { 'MY_VARIABLE': 42 })`
+// Then, you can use %MY_VARIABLE% in your `index.html`.
+
+// It works in tandem with HtmlWebpackPlugin.
+// Learn more about creating plugins like this:
+// https://github.com/ampedandwired/html-webpack-plugin#events
+
+'use strict';
+const escapeStringRegexp = require('escape-string-regexp');
+
+class InterpolateHtmlPlugin {
+  constructor(htmlWebpackPlugin, replacements) {
+    this.htmlWebpackPlugin = htmlWebpackPlugin;
+    this.replacements = replacements;
+  }
+
+  apply(compiler) {
+    compiler.hooks.compilation.tap('InterpolateHtmlPlugin', compilation => {
+      this.htmlWebpackPlugin
+        .getHooks(compilation)
+        .afterTemplateExecution.tap('InterpolateHtmlPlugin', data => {
+          // Run HTML through a series of user-specified string replacements.
+          Object.keys(this.replacements).forEach(key => {
+            const value = this.replacements[key];
+            data.html = data.html.replace(
+              new RegExp('%' + escapeStringRegexp(key) + '%', 'g'),
+              value
+            );
+          });
+        });
+    });
+  }
+}
+
+module.exports = InterpolateHtmlPlugin;