diff --git a/.eslintignore b/.eslintignore
index f2808fd85fda..c129ac2d909d 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -50,7 +50,6 @@ browser/components/pocket/content/panels/js/vendor/**
 # Kept in sync with browser/components/newtab/.eslintignore
 browser/components/newtab/data/
 browser/components/newtab/logs/
-browser/components/newtab/prerendered/
 browser/components/newtab/vendor/
 
 # The only file in browser/locales/ is pre-processed.
diff --git a/.gitignore b/.gitignore
index 6dce310d1017..793124c263da 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,8 +44,6 @@ security/manager/.nss.checkout
 /gecko.log
 
 # Ignore newtab component build assets
-browser/components/newtab/bin/prerender.js
-browser/components/newtab/bin/prerender.js.map
 browser/components/newtab/data/locales.json
 browser/components/newtab/logs/
 
diff --git a/browser/base/content/test/static/browser_all_files_referenced.js b/browser/base/content/test/static/browser_all_files_referenced.js
index cc1dcdc200e3..ff1ece127f74 100644
--- a/browser/base/content/test/static/browser_all_files_referenced.js
+++ b/browser/base/content/test/static/browser_all_files_referenced.js
@@ -34,8 +34,6 @@ var gExceptionPaths = [
 
   // https://github.com/mozilla/activity-stream/issues/3053
   "resource://activity-stream/data/content/tippytop/images/",
-  // https://github.com/mozilla/activity-stream/issues/3758
-  "resource://activity-stream/prerendered/",
 
   // browser/extensions/pdfjs/content/build/pdf.js#1999
   "resource://pdf.js/web/images/",
diff --git a/browser/components/newtab/.eslintignore b/browser/components/newtab/.eslintignore
index f7f27c26afe9..162021863389 100644
--- a/browser/components/newtab/.eslintignore
+++ b/browser/components/newtab/.eslintignore
@@ -1,4 +1,3 @@
 data/
 logs/
-prerendered/
 vendor/
diff --git a/browser/components/newtab/AboutNewTabService.jsm b/browser/components/newtab/AboutNewTabService.jsm
index 4745ef17a613..6525ce6295dd 100644
--- a/browser/components/newtab/AboutNewTabService.jsm
+++ b/browser/components/newtab/AboutNewTabService.jsm
@@ -14,13 +14,8 @@ ChromeUtils.defineModuleGetter(this, "AboutNewTab",
                                "resource:///modules/AboutNewTab.jsm");
 
 const TOPIC_APP_QUIT = "quit-application-granted";
-const TOPIC_LOCALES_CHANGE = "intl:app-locales-changed";
 const TOPIC_CONTENT_DOCUMENT_INTERACTIVE = "content-document-interactive";
 
-// Automated tests ensure packaged locales are in this list. Copied output of:
-// https://github.com/mozilla/activity-stream/blob/master/bin/render-activity-stream-html.js
-const ACTIVITY_STREAM_BCP47 = "en-US".split(" ");
-
 const ABOUT_URL = "about:newtab";
 const BASE_URL = "resource://activity-stream/";
 const ACTIVITY_STREAM_PAGES = new Set(["home", "newtab", "welcome"]);
@@ -35,7 +30,6 @@ const PREF_ACTIVITY_STREAM_DEBUG = "browser.newtabpage.activity-stream.debug";
 
 function AboutNewTabService() {
   Services.obs.addObserver(this, TOPIC_APP_QUIT);
-  Services.obs.addObserver(this, TOPIC_LOCALES_CHANGE);
   Services.prefs.addObserver(PREF_SEPARATE_PRIVILEGEDABOUT_CONTENT_PROCESS, this);
   if (!IS_RELEASE_OR_BETA) {
     Services.prefs.addObserver(PREF_ACTIVITY_STREAM_DEBUG, this);
@@ -71,7 +65,7 @@ function AboutNewTabService() {
  *
  * When the URL loaded is about:newtab, the default behavior, or when entered in the
  * URL bar, the redirector is hit. The service is then called to return the
- * appropriate activity stream url based on prefs and locales.
+ * appropriate activity stream url based on prefs.
  *
  * NOTE: "about:newtab" will always result in a default newtab page, and never an overridden URL.
  *
@@ -88,7 +82,6 @@ AboutNewTabService.prototype = {
 
   _newTabURL: ABOUT_URL,
   _activityStreamEnabled: false,
-  _activityStreamPath: "",
   _activityStreamDebug: false,
   _privilegedAboutContentProcess: false,
   _overridden: false,
@@ -105,11 +98,9 @@ AboutNewTabService.prototype = {
       case "nsPref:changed":
         if (data === PREF_SEPARATE_PRIVILEGEDABOUT_CONTENT_PROCESS) {
           this._privilegedAboutContentProcess = Services.prefs.getBoolPref(PREF_SEPARATE_PRIVILEGEDABOUT_CONTENT_PROCESS);
-          this.updatePrerenderedPath();
           this.notifyChange();
         } else if (!IS_RELEASE_OR_BETA && data === PREF_ACTIVITY_STREAM_DEBUG) {
           this._activityStreamDebug = Services.prefs.getBoolPref(PREF_ACTIVITY_STREAM_DEBUG, false);
-          this.updatePrerenderedPath();
           this.notifyChange();
         }
         break;
@@ -147,7 +138,6 @@ AboutNewTabService.prototype = {
             `${BASE_URL}vendor/prop-types.js`,
             `${BASE_URL}vendor/redux.js`,
             `${BASE_URL}vendor/react-redux.js`,
-            `${BASE_URL}prerendered/${this.activityStreamLocale}/activity-stream-strings.js`,
             `${BASE_URL}data/content/activity-stream.bundle.js`,
           ];
 
@@ -174,10 +164,6 @@ AboutNewTabService.prototype = {
           Services.obs.removeObserver(this, TOPIC_CONTENT_DOCUMENT_INTERACTIVE);
         }
         break;
-      case TOPIC_LOCALES_CHANGE:
-        this.updatePrerenderedPath();
-        this.notifyChange();
-        break;
     }
   },
 
@@ -209,34 +195,23 @@ AboutNewTabService.prototype = {
     if (!IS_RELEASE_OR_BETA) {
       this._activityStreamDebug = Services.prefs.getBoolPref(PREF_ACTIVITY_STREAM_DEBUG, false);
     }
-    this.updatePrerenderedPath();
     this._newtabURL = ABOUT_URL;
     return true;
   },
 
-  /**
-   * Figure out what path under prerendered to use based on current state.
-   */
-  updatePrerenderedPath() {
-    // Debug files are specially packaged in a non-localized directory, but with
-    // dynamic script loading, localized debug is supported.
-    this._activityStreamPath = `${this._activityStreamDebug &&
-      !this._privilegedAboutContentProcess ? "static" : this.activityStreamLocale}/`;
-  },
-
   /*
    * Returns the default URL.
    *
-   * This URL depends on various activity stream prefs and locales. Overriding
+   * This URL depends on various activity stream prefs. Overriding
    * the newtab page has no effect on the result of this function.
    */
   get defaultURL() {
     // Generate the desired activity stream resource depending on state, e.g.,
-    // resource://activity-stream/prerendered/ar/activity-stream.html
-    // resource://activity-stream/prerendered/static/activity-stream-debug.html
+    // "resource://activity-stream/prerendered/activity-stream.html"
+    // "resource://activity-stream/prerendered/activity-stream-debug.html"
+    // "resource://activity-stream/prerendered/activity-stream-noscripts.html"
     return [
       "resource://activity-stream/prerendered/",
-      this._activityStreamPath,
       "activity-stream",
       // Debug version loads dev scripts but noscripts separately loads scripts
       this._activityStreamDebug && !this._privilegedAboutContentProcess ? "-debug" : "",
@@ -286,21 +261,6 @@ AboutNewTabService.prototype = {
     return this._activityStreamDebug;
   },
 
-  get activityStreamLocale() {
-    // Pick the best available locale to match the app locales
-    return Services.locale.negotiateLanguages(
-      // Fix up incorrect BCP47 that are actually lang tags as a workaround for
-      // bug 1479606 returning the wrong values in the content process
-      Services.locale.appLocalesAsBCP47.map(l => l.replace(/^(ja-JP-mac)$/, "$1os")),
-      ACTIVITY_STREAM_BCP47,
-      // defaultLocale's strings aren't necessarily packaged, but en-US' are
-      "en-US",
-      Services.locale.langNegStrategyLookup
-    // Convert the BCP47 to lang tag, which is what is used in our paths, as a
-    // workaround for bug 1478930 negotiating incorrectly with lang tags
-    )[0].replace(/^(ja-JP-mac)os$/, "$1");
-  },
-
   resetNewTabURL() {
     this._overridden = false;
     this._newTabURL = ABOUT_URL;
@@ -327,7 +287,6 @@ AboutNewTabService.prototype = {
       return;
     }
     Services.obs.removeObserver(this, TOPIC_APP_QUIT);
-    Services.obs.removeObserver(this, TOPIC_LOCALES_CHANGE);
     Services.prefs.removeObserver(PREF_SEPARATE_PRIVILEGEDABOUT_CONTENT_PROCESS, this);
     if (!IS_RELEASE_OR_BETA) {
       Services.prefs.removeObserver(PREF_ACTIVITY_STREAM_DEBUG, this);
diff --git a/browser/components/newtab/bin/render-activity-stream-html.js b/browser/components/newtab/bin/render-activity-stream-html.js
index 9970b4b068d0..b96c67176d00 100644
--- a/browser/components/newtab/bin/render-activity-stream-html.js
+++ b/browser/components/newtab/bin/render-activity-stream-html.js
@@ -3,8 +3,6 @@ const fs = require("fs");
 const {mkdir} = require("shelljs");
 const path = require("path");
 
-const {CENTRAL_LOCALES, DEFAULT_LOCALE} = require("./locales");
-
 // Note: DEFAULT_OPTIONS.baseUrl should match BASE_URL in aboutNewTabService.js
 //       in mozilla-central.
 const DEFAULT_OPTIONS = {
@@ -12,52 +10,11 @@ const DEFAULT_OPTIONS = {
   baseUrl: "resource://activity-stream/",
 };
 
-// Locales that should be displayed RTL
-const RTL_LIST = ["ar", "he", "fa", "ur"];
-
-/**
- * Get the language part of the locale.
- */
-function getLanguage(locale) {
-  return locale.split("-")[0];
-}
-
-/**
- * Get the best strings for a single provided locale using similar locales and
- * DEFAULT_LOCALE as fallbacks.
- */
-function getStrings(locale, allStrings) {
-  const availableLocales = Object.keys(allStrings);
-
-  const language = getLanguage(locale);
-  const similarLocales = availableLocales.filter(other =>
-    other !== locale && getLanguage(other) === language);
-
-  // Rank locales from least desired to most desired
-  const localeFallbacks = [DEFAULT_LOCALE, ...similarLocales, locale];
-
-  // Get strings from each locale replacing with those from more desired ones
-  const desired = Object.assign({}, ...localeFallbacks.map(l => allStrings[l]));
-
-  // Only include strings that are currently used (defined by default locale)
-  return Object.assign({}, ...Object.keys(allStrings[DEFAULT_LOCALE]).map(
-    key => ({[key]: desired[key]})));
-}
-
-/**
- * Get the text direction of the locale.
- */
-function getTextDirection(locale) {
-  return RTL_LIST.includes(locale.split("-")[0]) ? "rtl" : "ltr";
-}
-
 /**
  * templateHTML - Generates HTML for activity stream, given some options and
  * prerendered HTML if necessary.
  *
  * @param  {obj} options
- *         {str} options.locale         The locale to render in lang="" attribute
- *         {str} options.direction      The language direction to render in dir="" attribute
  *         {str} options.baseUrl        The base URL for all local assets
  *         {bool} options.debug         Should we use dev versions of JS libraries?
  *         {bool} options.noscripts     Should we include scripts in the prerendered files?
@@ -73,7 +30,6 @@ function templateHTML(options) {
     `${options.baseUrl}vendor/prop-types.js`,
     `${options.baseUrl}vendor/redux.js`,
     `${options.baseUrl}vendor/react-redux.js`,
-    `${options.baseUrl}prerendered/${options.locale}/activity-stream-strings.js`,
     `${options.baseUrl}data/content/activity-stream.bundle.js`,
   ];
 
@@ -81,7 +37,7 @@ function templateHTML(options) {
   const scriptRender = `\n${scripts.map(script => `    <script src="${script}"></script>`).join("\n")}`;
 
   return `<!doctype html>
-<html lang="${options.locale}" dir="${options.direction}">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -101,49 +57,24 @@ function templateHTML(options) {
 `;
 }
 
-/**
- * templateJs - Generates a js file that passes the initial state of the prerendered
- * DOM to the React version. This is necessary to ensure the checksum matches when
- * React mounts so that it can attach to the prerendered elements instead of blowing
- * them away.
- *
- * Note that this may no longer be necessary in React 16 and we should review whether
- * it is still necessary.
- *
- * @param  {string} name The name of the global to expose
- * @param  {string} desc Extra description to include in a js comment
- * @param  {obj}   state The data to expose as a window global
- * @return {str}         The js file as a string
- */
-function templateJs(name, desc, state) {
-  return `// Note - this is a generated ${desc} file.
-window.${name} = ${JSON.stringify(state, null, 2)};
-`;
-}
-
 /**
  * writeFiles - Writes to the desired files the result of a template given
  * various prerendered data and options.
  *
- * @param {string} name          Something to identify in the console
  * @param {string} destPath      Path to write the files to
  * @param {Map}    filesMap      Mapping of a string file name to templater
  * @param {Object} options       Various options for the templater
  */
-function writeFiles(name, destPath, filesMap, options) {
+function writeFiles(destPath, filesMap, options) {
   for (const [file, templater] of filesMap) {
+    console.log("\x1b[32m", `✓ ${file}`, "\x1b[0m");
     fs.writeFileSync(path.join(destPath, file), templater({options}));
   }
-  console.log("\x1b[32m", `✓ ${name}`, "\x1b[0m");
 }
 
 const STATIC_FILES = new Map([
-  ["activity-stream-debug.html", ({options}) => templateHTML(options)],
-]);
-
-const LOCALIZED_FILES = new Map([
-  ["activity-stream-strings.js", ({options: {locale, strings}}) => templateJs("gActivityStreamStrings", locale, strings)],
   ["activity-stream.html", ({options}) => templateHTML(options)],
+  ["activity-stream-debug.html", ({options}) => templateHTML(Object.assign({}, options, {debug: true}))],
   ["activity-stream-noscripts.html", ({options}) => templateHTML(Object.assign({}, options, {noscripts: true}))],
 ]);
 
@@ -162,74 +93,13 @@ function main() { // eslint-disable-line max-statements
     },
   });
 
-  const baseOptions = Object.assign({debug: false}, DEFAULT_OPTIONS, args || {});
-  const addonPath = path.resolve(__dirname, baseOptions.addonPath);
-  const allStrings = require(`${baseOptions.addonPath}/data/locales.json`);
-  const extraLocales = Object.keys(allStrings).filter(locale =>
-    locale !== DEFAULT_LOCALE && !CENTRAL_LOCALES.includes(locale));
-
+  const options = Object.assign({debug: false}, DEFAULT_OPTIONS, args || {});
+  const addonPath = path.resolve(__dirname, options.addonPath);
   const prerenderedPath = path.join(addonPath, "prerendered");
-  console.log(`Writing prerendered files to individual directories under ${prerenderedPath}:`);
+  console.log(`Writing prerendered files to ${prerenderedPath}:`);
 
-  // Save default locale's strings to compare against other locales' strings
-  let defaultStrings;
-  let langStrings;
-  const isSubset = (strings, existing) => existing &&
-    Object.keys(strings).every(key => strings[key] === existing[key]);
-
-  // Process the default locale first then all the ones from mozilla-central
-  const localizedLocales = [];
-  const skippedLocales = [];
-  for (const locale of [DEFAULT_LOCALE, ...CENTRAL_LOCALES]) {
-    // Skip the locale if it would have resulted in duplicate packaged files
-    const strings = getStrings(locale, allStrings);
-    if (isSubset(strings, defaultStrings) || isSubset(strings, langStrings)) {
-      skippedLocales.push(locale);
-      continue;
-    }
-
-    const options = Object.assign({}, baseOptions, {
-      direction: getTextDirection(locale),
-      locale,
-      strings,
-    });
-
-    // Put locale-specific files in their own directory
-    const localePath = path.join(prerenderedPath, "locales", locale);
-    mkdir("-p", localePath);
-    writeFiles(locale, localePath, LOCALIZED_FILES, options);
-
-    // Only write static files once for the default locale
-    if (locale === DEFAULT_LOCALE) {
-      const staticPath = path.join(prerenderedPath, "static");
-      mkdir("-p", staticPath);
-      writeFiles(`${locale} (static)`, staticPath, STATIC_FILES,
-        Object.assign({}, options, {debug: true}));
-
-      // Save the default strings to compare against other locales' strings
-      defaultStrings = strings;
-    }
-
-    // Save the language's strings to maybe reuse for the next similar locales
-    if (getLanguage(locale) === locale) {
-      langStrings = strings;
-    }
-
-    localizedLocales.push(locale);
-  }
-
-  if (skippedLocales.length) {
-    console.log("\x1b[33m", `Skipped the following locales because they use the same strings as ${DEFAULT_LOCALE} or its language locale: ${skippedLocales.join(", ")}`, "\x1b[0m");
-  }
-  if (extraLocales.length) {
-    console.log("\x1b[33m", `Skipped the following locales because they are not in CENTRAL_LOCALES: ${extraLocales.join(", ")}`, "\x1b[0m");
-  }
-
-  // Convert ja-JP-mac lang tag to ja-JP-macos bcp47 to work around bug 1478930
-  const bcp47String = localizedLocales.join(" ").replace(/(ja-JP-mac)/, "$1os");
-
-  // Provide some help to copy/paste locales if tests are failing
-  console.log(`\nIf aboutNewTabService tests are failing for unexpected locales, make sure its list is updated:\nconst ACTIVITY_STREAM_BCP47 = "${bcp47String}".split(" ");`);
+  mkdir("-p", prerenderedPath);
+  writeFiles(prerenderedPath, STATIC_FILES, options);
 }
 
 main();
diff --git a/browser/components/newtab/jar.mn b/browser/components/newtab/jar.mn
index b6c8437c25a8..edc64f186aa4 100644
--- a/browser/components/newtab/jar.mn
+++ b/browser/components/newtab/jar.mn
@@ -26,7 +26,8 @@ browser.jar:
 #else
   res/activity-stream/css/activity-stream.css (./css/activity-stream-linux.css)
 #endif
+  res/activity-stream/prerendered/activity-stream.html (./prerendered/activity-stream.html)
 #ifndef RELEASE_OR_BETA
-  res/activity-stream/prerendered/static/activity-stream-debug.html (./prerendered/static/activity-stream-debug.html)
+  res/activity-stream/prerendered/activity-stream-debug.html (./prerendered/activity-stream-debug.html)
 #endif
-  res/activity-stream/prerendered/ (./prerendered/locales/*)
+  res/activity-stream/prerendered/activity-stream-noscripts.html (./prerendered/activity-stream-noscripts.html)
diff --git a/browser/components/newtab/nsIAboutNewTabService.idl b/browser/components/newtab/nsIAboutNewTabService.idl
index a157bfdf82c1..e8b0593711a4 100644
--- a/browser/components/newtab/nsIAboutNewTabService.idl
+++ b/browser/components/newtab/nsIAboutNewTabService.idl
@@ -49,11 +49,6 @@ interface nsIAboutNewTabService : nsISupports
    */
   readonly attribute bool activityStreamDebug;
 
-  /**
-   * Returns the locale of the activity stream interface
-   */
-  readonly attribute ACString activityStreamLocale;
-
   /**
    * Resets to the default resource and also resets the
    * overridden attribute to false.
diff --git a/browser/components/newtab/prerendered/static/activity-stream-debug.html b/browser/components/newtab/prerendered/activity-stream-debug.html
similarity index 92%
rename from browser/components/newtab/prerendered/static/activity-stream-debug.html
rename to browser/components/newtab/prerendered/activity-stream-debug.html
index a35266b734ba..961f06cadf32 100644
--- a/browser/components/newtab/prerendered/static/activity-stream-debug.html
+++ b/browser/components/newtab/prerendered/activity-stream-debug.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -21,7 +21,6 @@
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
-    <script src="resource://activity-stream/prerendered/en-US/activity-stream-strings.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>
   </body>
 </html>
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html b/browser/components/newtab/prerendered/activity-stream-noscripts.html
similarity index 96%
rename from browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html
rename to browser/components/newtab/prerendered/activity-stream-noscripts.html
index aebe8bd0664c..bbe8f758070e 100644
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream-noscripts.html
+++ b/browser/components/newtab/prerendered/activity-stream-noscripts.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream.html b/browser/components/newtab/prerendered/activity-stream.html
similarity index 92%
rename from browser/components/newtab/prerendered/locales/en-US/activity-stream.html
rename to browser/components/newtab/prerendered/activity-stream.html
index d5f65ddf14a7..2c248121ed2d 100644
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream.html
+++ b/browser/components/newtab/prerendered/activity-stream.html
@@ -1,5 +1,5 @@
 <!doctype html>
-<html lang="en-US" dir="ltr">
+<html>
   <head>
     <meta charset="utf-8">
     <meta http-equiv="Content-Security-Policy" content="default-src 'none'; object-src 'none'; script-src resource: chrome:; connect-src https:; img-src https: data: blob:; style-src 'unsafe-inline';">
@@ -21,7 +21,6 @@
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
-    <script src="resource://activity-stream/prerendered/en-US/activity-stream-strings.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>
   </body>
 </html>
diff --git a/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js b/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js
deleted file mode 100644
index 67578c835f9a..000000000000
--- a/browser/components/newtab/prerendered/locales/en-US/activity-stream-strings.js
+++ /dev/null
@@ -1,2 +0,0 @@
-// Note - this is a generated en-US file.
-window.gActivityStreamStrings = {};
diff --git a/browser/components/newtab/test/xpcshell/test_AboutNewTabService.js b/browser/components/newtab/test/xpcshell/test_AboutNewTabService.js
index 1c76e0374fa7..9f93b98eedc3 100644
--- a/browser/components/newtab/test/xpcshell/test_AboutNewTabService.js
+++ b/browser/components/newtab/test/xpcshell/test_AboutNewTabService.js
@@ -29,12 +29,12 @@ let ACTIVITY_STREAM_URL;
 let ACTIVITY_STREAM_DEBUG_URL;
 
 function setExpectedUrlsWithScripts() {
-  ACTIVITY_STREAM_URL = "resource://activity-stream/prerendered/en-US/activity-stream.html";
-  ACTIVITY_STREAM_DEBUG_URL = "resource://activity-stream/prerendered/static/activity-stream-debug.html";
+  ACTIVITY_STREAM_URL = "resource://activity-stream/prerendered/activity-stream.html";
+  ACTIVITY_STREAM_DEBUG_URL = "resource://activity-stream/prerendered/activity-stream-debug.html";
 }
 
 function setExpectedUrlsWithoutScripts() {
-  ACTIVITY_STREAM_URL = "resource://activity-stream/prerendered/en-US/activity-stream-noscripts.html";
+  ACTIVITY_STREAM_URL = "resource://activity-stream/prerendered/activity-stream-noscripts.html";
 
   // Debug urls are the same as non-debug because debug scripts load dynamically
   ACTIVITY_STREAM_DEBUG_URL = ACTIVITY_STREAM_URL;
@@ -192,11 +192,6 @@ addTestsWithPrivilegedContentProcessPref(async function test_welcome_url() {
   cleanup();
 });
 
-add_task(function test_locale() {
-  Assert.equal(aboutNewTabService.activityStreamLocale, "en-US",
-    "The locale for testing should be en-US");
-});
-
 /**
  * Tests response to updates to prefs
  */
diff --git a/tools/lint/codespell.yml b/tools/lint/codespell.yml
index 67e34d14af99..a1504333484e 100644
--- a/tools/lint/codespell.yml
+++ b/tools/lint/codespell.yml
@@ -5,7 +5,6 @@ codespell:
         - browser/base/content/docs/
         - browser/branding/
         - browser/components/newtab/docs/
-        - browser/components/newtab/prerendered/locales/en-US/
         - browser/extensions/formautofill/locales/en-US/
         - browser/extensions/report-site-issue/locales/en-US/
         - browser/installer/windows/docs/