diff --git a/development/builder.js b/development/builder.js
index 23a6d9714b..f2dfb46648 100644
--- a/development/builder.js
+++ b/development/builder.js
@@ -3,6 +3,7 @@ const AdmZip = require("adm-zip");
 const pathUtil = require("path");
 const compatibilityAliases = require("./compatibility-aliases");
 const parseMetadata = require("./parse-extension-metadata");
+const { mkdirp, recursiveReadDirectory } = require("./fs-utils");
 
 /**
  * @typedef {'development'|'production'|'desktop'} Mode
@@ -14,52 +15,6 @@ const parseMetadata = require("./parse-extension-metadata");
  * @property {string} developer_comment Helper text to help translators
  */
 
-/**
- * Recursively read a directory.
- * @param {string} directory
- * @returns {Array<[string, string]>} List of tuples [name, absolutePath].
- * The return result includes files in subdirectories, but not the subdirectories themselves.
- */
-const recursiveReadDirectory = (directory) => {
-  const result = [];
-  for (const name of fs.readdirSync(directory)) {
-    if (name.startsWith(".")) {
-      // Ignore .eslintrc.js, .DS_Store, etc.
-      continue;
-    }
-    const absolutePath = pathUtil.join(directory, name);
-    const stat = fs.statSync(absolutePath);
-    if (stat.isDirectory()) {
-      for (const [
-        relativeToChildName,
-        childAbsolutePath,
-      ] of recursiveReadDirectory(absolutePath)) {
-        // This always needs to use / on all systems
-        result.push([`${name}/${relativeToChildName}`, childAbsolutePath]);
-      }
-    } else {
-      result.push([name, absolutePath]);
-    }
-  }
-  return result;
-};
-
-/**
- * Synchronous create a directory and any parents. Does nothing if the folder already exists.
- * @param {string} directory
- */
-const mkdirp = (directory) => {
-  try {
-    fs.mkdirSync(directory, {
-      recursive: true,
-    });
-  } catch (e) {
-    if (e.code !== "ENOENT") {
-      throw e;
-    }
-  }
-};
-
 /**
  * @param {Record<string, Record<string, string>>} allTranslations
  * @param {string} idPrefix
diff --git a/development/fs-utils.js b/development/fs-utils.js
new file mode 100644
index 0000000000..020a1e9d98
--- /dev/null
+++ b/development/fs-utils.js
@@ -0,0 +1,53 @@
+const fs = require("fs");
+const pathUtil = require("path");
+
+/**
+ * Recursively read a directory.
+ * @param {string} directory
+ * @returns {Array<[string, string]>} List of tuples [name, absolutePath].
+ * The return result includes files in subdirectories, but not the subdirectories themselves.
+ */
+const recursiveReadDirectory = (directory) => {
+  const result = [];
+  for (const name of fs.readdirSync(directory)) {
+    if (name.startsWith(".")) {
+      // Ignore .eslintrc.js, .DS_Store, etc.
+      continue;
+    }
+    const absolutePath = pathUtil.join(directory, name);
+    const stat = fs.statSync(absolutePath);
+    if (stat.isDirectory()) {
+      for (const [
+        relativeToChildName,
+        childAbsolutePath,
+      ] of recursiveReadDirectory(absolutePath)) {
+        // This always needs to use / on all systems
+        result.push([`${name}/${relativeToChildName}`, childAbsolutePath]);
+      }
+    } else {
+      result.push([name, absolutePath]);
+    }
+  }
+  return result;
+};
+
+/**
+ * Synchronous create a directory and any parents. Does nothing if the folder already exists.
+ * @param {string} directory
+ */
+const mkdirp = (directory) => {
+  try {
+    fs.mkdirSync(directory, {
+      recursive: true,
+    });
+  } catch (e) {
+    if (e.code !== "ENOENT") {
+      throw e;
+    }
+  }
+};
+
+module.exports = {
+  recursiveReadDirectory,
+  mkdirp,
+};
diff --git a/development/get-credits-for-gui.js b/development/get-credits-for-gui.js
new file mode 100644
index 0000000000..22465e525c
--- /dev/null
+++ b/development/get-credits-for-gui.js
@@ -0,0 +1,118 @@
+const fs = require("fs");
+const path = require("path");
+const https = require("https");
+const fsUtils = require("./fs-utils");
+const parseMetadata = require("./parse-extension-metadata");
+
+class AggregatePersonInfo {
+  /** @param {Person} person */
+  constructor(person) {
+    this.name = person.name;
+
+    /** @type {Set<string>} */
+    this.links = new Set();
+  }
+
+  /** @param {string} link */
+  addLink(link) {
+    this.links.add(link);
+  }
+}
+
+/**
+ * @param {string} username
+ * @returns {Promise<string>}
+ */
+const getUserID = (username) =>
+  new Promise((resolve, reject) => {
+    process.stdout.write(`Getting user ID for ${username}... `);
+    const request = https.get(`https://api.scratch.mit.edu/users/${username}`);
+
+    request.on("response", (response) => {
+      const data = [];
+      response.on("data", (newData) => {
+        data.push(newData);
+      });
+
+      response.on("end", () => {
+        const allData = Buffer.concat(data);
+        const json = JSON.parse(allData.toString("utf-8"));
+        const userID = String(json.id);
+        process.stdout.write(`${userID}\n`);
+        resolve(userID);
+      });
+
+      response.on("error", (error) => {
+        process.stdout.write("error\n");
+        reject(error);
+      });
+    });
+
+    request.on("error", (error) => {
+      process.stdout.write("error\n");
+      reject(error);
+    });
+
+    request.end();
+  });
+
+const run = async () => {
+  /**
+   * @type {Map<string, AggregatePersonInfo>}
+   */
+  const aggregate = new Map();
+
+  const extensionRoot = path.resolve(__dirname, "../extensions/");
+  for (const [name, absolutePath] of fsUtils.recursiveReadDirectory(
+    extensionRoot
+  )) {
+    if (!name.endsWith(".js")) {
+      continue;
+    }
+
+    const code = fs.readFileSync(absolutePath, "utf-8");
+    const metadata = parseMetadata(code);
+
+    for (const person of [...metadata.by, ...metadata.original]) {
+      const personID = person.name.toLowerCase();
+      if (!aggregate.has(personID)) {
+        aggregate.set(personID, new AggregatePersonInfo(person));
+      }
+
+      if (person.link) {
+        aggregate.get(personID).addLink(person.link);
+      }
+    }
+  }
+
+  const result = [];
+
+  for (const id of [...aggregate.keys()].sort()) {
+    const info = aggregate.get(id);
+
+    if (info.links.size > 0) {
+      const link = [...info.links.values()].sort()[0];
+      const username = link.match(/users\/(.+?)\/?$/)[1];
+      const userID = await getUserID(username);
+      result.push({
+        userID,
+        username,
+      });
+    } else {
+      result.push({
+        username: info.name,
+      });
+    }
+  }
+
+  return result;
+};
+
+run()
+  .then((result) => {
+    console.log(JSON.stringify(result, null, 4));
+  })
+  .catch((error) => {
+    console.error(error);
+    process.exit(1);
+  });