diff --git a/build-system/test-configs/dep-check-config.js b/build-system/test-configs/dep-check-config.js
index c4dde1e5efbd..ab5bfcdd9984 100644
--- a/build-system/test-configs/dep-check-config.js
+++ b/build-system/test-configs/dep-check-config.js
@@ -329,6 +329,8 @@ exports.rules = [
       // Parsing extension urls.
       'extensions/amp-a4a/0.1/head-validation.js->' +
         'src/service/extension-script.js',
+      'extensions/amp-a4a/0.1/amp-ad-utils.js->' +
+        'src/service/extension-script.js',
       'extensions/amp-live-list/0.1/live-list-manager.js->' +
         'src/service/extension-script.js',
       'extensions/amp-video/0.1/amp-video.js->' +
diff --git a/extensions/amp-a4a/0.1/amp-a4a.js b/extensions/amp-a4a/0.1/amp-a4a.js
index e0caf4627b4e..ffac128b5467 100644
--- a/extensions/amp-a4a/0.1/amp-a4a.js
+++ b/extensions/amp-a4a/0.1/amp-a4a.js
@@ -57,12 +57,13 @@ import {
 } from '../../../src/consent';
 import {getContextMetadata} from '../../../src/iframe-attributes';
 import {getExperimentBranch, isExperimentOn} from '../../../src/experiments';
+import {getExtensionsFromMetadata} from './amp-ad-utils';
 import {getMode} from '../../../src/mode';
 import {insertAnalyticsElement} from '../../../src/extension-analytics';
 import {
   installFriendlyIframeEmbed,
   isSrcdocSupported,
-  preloadFriendlyIframeEmbedExtensionIdsDeprecated,
+  preloadFriendlyIframeEmbedExtensions,
 } from '../../../src/friendly-iframe-embed';
 import {installRealTimeConfigServiceForDoc} from '../../../src/service/real-time-config/real-time-config-impl';
 import {installUrlReplacementsForEmbed} from '../../../src/service/url-replacements-impl';
@@ -1122,12 +1123,8 @@ export class AmpA4A extends AMP.BaseElement {
 
           // Load any extensions; do not wait on their promises as this
           // is just to prefetch.
-          // TODO(#33020): switch to `preloadFriendlyIframeEmbedExtensions` with
-          // the format of `[{extensionId, extensionVersion}]`.
-          preloadFriendlyIframeEmbedExtensionIdsDeprecated(
-            this.win,
-            creativeMetaDataDef.customElementExtensions
-          );
+          const extensions = getExtensionsFromMetadata(creativeMetaDataDef);
+          preloadFriendlyIframeEmbedExtensions(this.win, extensions);
 
           // Preload any fonts.
           (creativeMetaDataDef.customStylesheets || []).forEach((font) =>
@@ -1825,13 +1822,9 @@ export class AmpA4A extends AMP.BaseElement {
       body
     );
 
-    // TODO(ccordry): FIE does not handle extension versioning, but we have
-    // it accessible here.
-    const extensionIds = extensions.map((extension) => extension.extensionId);
-
     const fieInstallPromise = this.installFriendlyIframeEmbed_(
       secureDoc,
-      extensionIds,
+      extensions,
       fonts,
       true // skipHtmlMerge
     );
@@ -1845,6 +1838,7 @@ export class AmpA4A extends AMP.BaseElement {
       }
     );
 
+    const extensionIds = extensions.map((extension) => extension.extensionId);
     return fieInstallPromise.then((friendlyIframeEmbed) => {
       checkStillCurrent();
       this.makeFieVisible_(
@@ -1906,10 +1900,11 @@ export class AmpA4A extends AMP.BaseElement {
       });
     }
     const checkStillCurrent = this.verifyStillCurrent();
-    const {minifiedCreative, customElementExtensions} = creativeMetaData;
+    const {minifiedCreative} = creativeMetaData;
+    const extensions = getExtensionsFromMetadata(creativeMetaData);
     return this.installFriendlyIframeEmbed_(
       minifiedCreative,
-      customElementExtensions,
+      extensions,
       fontsArray || [],
       false // skipHtmlMerge
     ).then((friendlyIframeEmbed) =>
@@ -1924,12 +1919,12 @@ export class AmpA4A extends AMP.BaseElement {
   /**
    * Convert the iframe to FIE impl and append to DOM.
    * @param {string} html
-   * @param {!Array<string>} extensionIds
+   * @param {!Array<{extensionId: string, extensionVersion: string}>} extensions
    * @param {!Array<string>} fonts
    * @param {boolean} skipHtmlMerge
    * @return {!Promise<!../../../src/friendly-iframe-embed.FriendlyIframeEmbed>}
    */
-  installFriendlyIframeEmbed_(html, extensionIds, fonts, skipHtmlMerge) {
+  installFriendlyIframeEmbed_(html, extensions, fonts, skipHtmlMerge) {
     return installFriendlyIframeEmbed(
       devAssert(this.iframe),
       this.element,
@@ -1938,9 +1933,7 @@ export class AmpA4A extends AMP.BaseElement {
         // Need to guarantee that this is no longer null
         url: devAssert(this.adUrl_),
         html,
-        // TODO(#33020): provide the `extensions` property instead, in
-        // the format of `[{extensionId, extensionVersion}]`.
-        extensionIds,
+        extensions,
         fonts,
         skipHtmlMerge,
       },
@@ -2263,6 +2256,9 @@ export class AmpA4A extends AMP.BaseElement {
       } else {
         metaData.customElementExtensions = [];
       }
+      if (metaDataObj['extensions']) {
+        metaData.extensions = metaDataObj['extensions'];
+      }
       if (metaDataObj['customStylesheets']) {
         // Expect array of objects with at least one key being 'href' whose
         // value is URL.
diff --git a/extensions/amp-a4a/0.1/amp-ad-utils.js b/extensions/amp-a4a/0.1/amp-ad-utils.js
index 30a3275c6957..bcd3cf7d7e16 100644
--- a/extensions/amp-a4a/0.1/amp-ad-utils.js
+++ b/extensions/amp-a4a/0.1/amp-ad-utils.js
@@ -17,6 +17,7 @@ import {Services} from '../../../src/services';
 import {dev} from '../../../src/log';
 import {isArray, isObject} from '../../../src/types';
 import {isSecureUrlDeprecated} from '../../../src/url';
+import {parseExtensionUrl} from '../../../src/service/extension-script';
 import {parseJson} from '../../../src/json';
 
 const TAG = 'amp-ad-util';
@@ -160,3 +161,35 @@ export function getAmpAdMetadata(creative) {
     return null;
   }
 }
+
+/**
+ * Determine if parsed extensions metadata contains given element id.
+ * @param {!Array<{custom-element: string, src: string}>} extensions
+ * @param {string} id
+ * @return {boolean}
+ */
+export function extensionsHasElement(extensions, id) {
+  return extensions.some((entry) => entry['custom-element'] === id);
+}
+
+/**
+ * Parses extension urls from given metadata to retrieve name and version.
+ * @param {!./amp-ad-type-defs.CreativeMetaDataDef} creativeMetadata
+ * @return {!Array<?{extensionId: string, extensionVersion: string}>}
+ */
+export function getExtensionsFromMetadata(creativeMetadata) {
+  const parsedExtensions = [];
+  const {extensions} = creativeMetadata;
+  if (!extensions || !isArray(extensions)) {
+    return parsedExtensions;
+  }
+
+  for (let i = 0; i < extensions.length; i++) {
+    const extension = extensions[i];
+    const extensionData = parseExtensionUrl(extension.src);
+    if (extensionData) {
+      parsedExtensions.push(extensionData);
+    }
+  }
+  return parsedExtensions;
+}
diff --git a/extensions/amp-a4a/0.1/friendly-frame-util.js b/extensions/amp-a4a/0.1/friendly-frame-util.js
index d2f7b033c08e..0db1b021780c 100644
--- a/extensions/amp-a4a/0.1/friendly-frame-util.js
+++ b/extensions/amp-a4a/0.1/friendly-frame-util.js
@@ -17,12 +17,13 @@
 import {A4AVariableSource} from '../../amp-a4a/0.1/a4a-variable-source';
 import {createElementWithAttributes} from '../../../src/dom';
 import {dict} from '../../../src/utils/object';
+import {getExtensionsFromMetadata} from './amp-ad-utils';
 import {installFriendlyIframeEmbed} from '../../../src/friendly-iframe-embed';
 import {installUrlReplacementsForEmbed} from '../../../src/service/url-replacements-impl';
 import {setStyle} from '../../../src/style';
 
 /**
- * Renders a creative into a "NameFrame" iframe.
+ * Renders a creative into a friendly iframe.
  *
  * @param {string} adUrl The ad request URL.
  * @param {!./amp-ad-type-defs.LayoutInfoDef} size The size and layout of the
@@ -66,6 +67,7 @@ export function renderCreativeIntoFriendlyFrame(
     });
   }
 
+  const extensions = getExtensionsFromMetadata(creativeMetadata);
   return installFriendlyIframeEmbed(
     iframe,
     element,
@@ -73,9 +75,7 @@ export function renderCreativeIntoFriendlyFrame(
       host: element,
       url: /** @type {string} */ (adUrl),
       html: creativeMetadata.minifiedCreative,
-      // TODO(#33020): provide the `extensions` property instead, in
-      // the format of `[{extensionId, extensionVersion}]`.
-      extensionIds: creativeMetadata.customElementExtensions || [],
+      extensions,
       fonts: fontsArray,
     },
     (embedWin, ampdoc) => {
diff --git a/extensions/amp-a4a/0.1/template-validator.js b/extensions/amp-a4a/0.1/template-validator.js
index 894cc89c95f4..f0a395bbe97e 100644
--- a/extensions/amp-a4a/0.1/template-validator.js
+++ b/extensions/amp-a4a/0.1/template-validator.js
@@ -15,11 +15,15 @@
  */
 
 import {AdResponseType, Validator, ValidatorResult} from './amp-ad-type-defs';
-import {getAmpAdMetadata} from './amp-ad-utils';
+import {
+  extensionsHasElement,
+  getAmpAdMetadata,
+  getExtensionsFromMetadata,
+} from './amp-ad-utils';
 import {getAmpAdTemplateHelper} from './amp-ad-template-helper';
-import {preloadFriendlyIframeEmbedExtensionIdsDeprecated} from '../../../src/friendly-iframe-embed';
-import {pushIfNotExist} from '../../../src/utils/array';
+import {preloadFriendlyIframeEmbedExtensions} from '../../../src/friendly-iframe-embed';
 import {tryParseJson} from '../../../src/json';
+import {urls} from '../../../src/config';
 import {utf8Decode} from '../../../src/utils/bytes';
 
 /** @const {string} */
@@ -65,21 +69,26 @@ export class TemplateValidator extends Validator {
       .fetch(parsedResponseBody.templateUrl)
       .then((template) => {
         const creativeMetadata = getAmpAdMetadata(template);
-        const customElementExtensions =
-          creativeMetadata['customElementExtensions'];
-        if (parsedResponseBody.analytics) {
-          pushIfNotExist(customElementExtensions, 'amp-analytics');
+        creativeMetadata['extensions'] = creativeMetadata['extensions'] || [];
+        const extensions = creativeMetadata['extensions'];
+        if (
+          parsedResponseBody.analytics &&
+          !extensionsHasElement(extensions, 'amp-analytics')
+        ) {
+          extensions.push({
+            'custom-element': 'amp-analytics',
+            src: `${urls.cdn}/v0/amp-analytics-0.1.js`,
+          });
+        }
+        if (!extensionsHasElement(extensions, 'amp-mustache')) {
+          extensions.push({
+            'custom-element': 'amp-mustache',
+            src: `${urls.cdn}/v0/amp-mustache-latest.js`,
+          });
         }
-        pushIfNotExist(customElementExtensions, 'amp-mustache');
 
-        // Load any extensions; do not wait on their promises as this
-        // is just to prefetch.
-        // TODO(#33020): switch to `preloadFriendlyIframeEmbedExtensions` with
-        // the format of `[{extensionId, extensionVersion}]`.
-        preloadFriendlyIframeEmbedExtensionIdsDeprecated(
-          context.win,
-          customElementExtensions
-        );
+        const extensionsInfo = getExtensionsFromMetadata(creativeMetadata);
+        preloadFriendlyIframeEmbedExtensions(context.win, extensionsInfo);
 
         // TODO(levitzky) Add preload logic for fonts / images.
         return Promise.resolve(
diff --git a/extensions/amp-a4a/0.1/test/test-amp-a4a.js b/extensions/amp-a4a/0.1/test/test-amp-a4a.js
index 8c7e2c9b5927..2426ec86ec2e 100644
--- a/extensions/amp-a4a/0.1/test/test-amp-a4a.js
+++ b/extensions/amp-a4a/0.1/test/test-amp-a4a.js
@@ -2352,6 +2352,28 @@ describes.realWin('amp-a4a', {amp: true}, (env) => {
       expect(actual).to.deep.equal(expected);
     });
 
+    it('should copy over any extensions detail', () => {
+      metaData.extensions = [
+        {
+          'custom-element': 'amp-analytics',
+          'src': 'https://cdn.ampproject.org/v0/amp-analytics-0.1.js',
+        },
+        {
+          'custom-element': 'amp-mustache',
+          'src': 'https://cdn.ampproject.org/v0/amp-mustache-1.0.js',
+        },
+      ];
+      const actual = a4a.getAmpAdMetadata(buildCreativeString(metaData));
+      expect(actual.extensions).to.deep.include({
+        'custom-element': 'amp-analytics',
+        'src': 'https://cdn.ampproject.org/v0/amp-analytics-0.1.js',
+      });
+      expect(actual.extensions).to.deep.include({
+        'custom-element': 'amp-mustache',
+        'src': 'https://cdn.ampproject.org/v0/amp-mustache-1.0.js',
+      });
+    });
+
     // TODO(levitzky) remove the following two tests after metadata bug is
     // fixed.
     it('should parse metadata with wrong opening tag', () => {
diff --git a/extensions/amp-a4a/0.1/test/test-amp-ad-utils.js b/extensions/amp-a4a/0.1/test/test-amp-ad-utils.js
index 47cde5ec42b2..91a0da5d299e 100644
--- a/extensions/amp-a4a/0.1/test/test-amp-ad-utils.js
+++ b/extensions/amp-a4a/0.1/test/test-amp-ad-utils.js
@@ -15,7 +15,11 @@
  */
 
 import {data} from './testdata/valid_css_at_rules_amp.reserialized';
-import {getAmpAdMetadata} from '../amp-ad-utils';
+import {
+  extensionsHasElement,
+  getAmpAdMetadata,
+  getExtensionsFromMetadata,
+} from '../amp-ad-utils';
 
 describe('getAmpAdMetadata', () => {
   it('should parse metadata successfully', () => {
@@ -56,3 +60,62 @@ describe('getAmpAdMetadata', () => {
     expect(creativeMetadata).to.be.null;
   });
 });
+
+describe('extensionsHasElement', () => {
+  it('should return true if containing extension', () => {
+    const extensions = [
+      {
+        'custom-element': 'amp-cats',
+        src: 'https://cdn.ampproject.org/v0/amp-cats-0.1.js',
+      },
+    ];
+    expect(extensionsHasElement(extensions, 'amp-cats')).to.be.true;
+  });
+
+  it('should return false if it does not contain extension', () => {
+    const extensions = [
+      {
+        'custom-element': 'amp-cats',
+        src: 'https://cdn.ampproject.org/v0/amp-cats-0.1.js',
+      },
+    ];
+    expect(extensionsHasElement(extensions, 'amp-dogs')).to.be.false;
+  });
+
+  it('should return false if empty array', () => {
+    const extensions = [];
+    expect(extensionsHasElement(extensions, 'amp-dogs')).to.be.false;
+  });
+});
+
+describe('getExtensionsFromMetadata', () => {
+  it('should return extension name and version', () => {
+    const metadata = {
+      extensions: [
+        {
+          'custom-element': 'amp-analytics',
+          'src': 'https://cdn.ampproject.org/v0/amp-analytics-0.1.js',
+        },
+        {
+          'custom-element': 'amp-mustache',
+          'src': 'https://cdn.ampproject.org/v0/amp-mustache-1.0.js',
+        },
+      ],
+    };
+    const extensions = getExtensionsFromMetadata(metadata);
+    expect(extensions).to.deep.include({
+      extensionId: 'amp-analytics',
+      extensionVersion: '0.1',
+    });
+    expect(extensions).to.deep.include({
+      extensionId: 'amp-mustache',
+      extensionVersion: '1.0',
+    });
+  });
+
+  it('should handle no `extensions` key in metadata', () => {
+    const metadata = {};
+    const extensions = getExtensionsFromMetadata(metadata);
+    expect(extensions).to.eql([]);
+  });
+});
diff --git a/extensions/amp-a4a/0.1/test/test-template-validator.js b/extensions/amp-a4a/0.1/test/test-template-validator.js
index 3e04adb189f3..e11827b2e96a 100644
--- a/extensions/amp-a4a/0.1/test/test-template-validator.js
+++ b/extensions/amp-a4a/0.1/test/test-template-validator.js
@@ -130,15 +130,19 @@ describes.realWin('TemplateValidator', realWinConfig, (env) => {
       });
     });
 
-    it('should have amp-analytics and mustache in customElementExtensions', () => {
+    it('should have amp-analytics and mustache in extensions', () => {
       return validatorPromise.then((validatorOutput) => {
         expect(validatorOutput).to.be.ok;
         expect(validatorOutput.creativeData).to.be.ok;
         const {creativeMetadata} = validatorOutput.creativeData;
-        expect(creativeMetadata.customElementExtensions).to.deep.equal([
-          'amp-analytics',
-          'amp-mustache',
-        ]);
+        expect(creativeMetadata.extensions).to.deep.include({
+          'custom-element': 'amp-analytics',
+          'src': 'https://cdn.ampproject.org/v0/amp-analytics-0.1.js',
+        });
+        expect(creativeMetadata.extensions).to.deep.include({
+          'custom-element': 'amp-mustache',
+          'src': 'https://cdn.ampproject.org/v0/amp-mustache-latest.js',
+        });
       });
     });
   });
diff --git a/extensions/amp-story/1.0/test/test-amp-story-page.js b/extensions/amp-story/1.0/test/test-amp-story-page.js
index 73f395ddb93b..08917580aa43 100644
--- a/extensions/amp-story/1.0/test/test-amp-story-page.js
+++ b/extensions/amp-story/1.0/test/test-amp-story-page.js
@@ -251,6 +251,7 @@ describes.realWin('amp-story-page', {amp: {extensions}}, (env) => {
     const fiePromise = installFriendlyIframeEmbed(iframe, gridLayerEl, {
       url: 'https://amp.dev',
       html: '<video src="https://example.com/video.mp3"></video>',
+      extensions: [],
     });
     env.sandbox.stub(page, 'loadPromise').returns(Promise.resolve());
 
diff --git a/src/friendly-iframe-embed.js b/src/friendly-iframe-embed.js
index 012c78b03315..e013b17e08e5 100644
--- a/src/friendly-iframe-embed.js
+++ b/src/friendly-iframe-embed.js
@@ -62,14 +62,12 @@ import {whenContentIniLoad} from './ini-load';
  *   this embed.
  * - fonts: An optional array of fonts used in this embed.
  *
- * TODO(#33020): remove extensionIds once extensions is used everywhere.
  *
  * @typedef {{
  *   host: (?AmpElement|undefined),
  *   url: string,
  *   html: ?string,
  *   extensions: (?Array<{extensionId: string, extensionVersion: string}>|undefined),
- *   extensionIds: (?Array<string>|undefined),
  *   fonts: (?Array<string>|undefined),
  *   skipHtmlMerge: (boolean|undefined),
  * }}
@@ -137,6 +135,7 @@ export function preloadFriendlyIframeEmbedExtensions(win, extensions) {
  * @param {!Window} win
  * @param {!Array<string>} extensionIds
  * TODO(#33020): remove this method in favor `preloadFriendlyIframeEmbedExtensions`.
+ * @visibleForTesting
  */
 export function preloadFriendlyIframeEmbedExtensionIdsDeprecated(
   win,
@@ -180,17 +179,8 @@ export function installFriendlyIframeEmbed(
   iframe.setAttribute('marginheight', '0');
   iframe.setAttribute('marginwidth', '0');
 
-  // Compute extensions.
-  const extensionIds =
-    // TODO(#33020): Remove extensionIds format once it's supported everywhere.
-    spec.extensionIds
-      ? spec.extensionIds
-      : spec.extensions
-      ? spec.extensions.map(({extensionId}) => extensionId)
-      : [];
-
   // Pre-load extensions.
-  preloadFriendlyIframeEmbedExtensionIdsDeprecated(win, extensionIds);
+  preloadFriendlyIframeEmbedExtensions(win, spec.extensions || []);
 
   const html = spec.skipHtmlMerge ? spec.html : mergeHtml(spec);
   // Receive the signal when iframe is ready: it's document is formed.
@@ -274,7 +264,7 @@ export function installFriendlyIframeEmbed(
       embed,
       extensionsService,
       ampdoc,
-      extensionIds,
+      spec.extensions,
       opt_preinstallCallback
     ).then(() => {
       if (!childWin.frameElement) {
@@ -746,7 +736,7 @@ export class Installers {
    * @param {!FriendlyIframeEmbed} embed
    * @param {!./service/extensions-impl.Extensions} extensionsService
    * @param {!./service/ampdoc-impl.AmpDocFie} ampdoc
-   * @param {!Array<string>} extensionIds
+   * @param {!Array<{extensionId: string, extensionVersion: string}>} extensions
    * @param {function(!Window, ?./service/ampdoc-impl.AmpDoc=)|undefined} preinstallCallback
    * @param {function(!Promise)=} opt_installComplete
    * @return {!Promise}
@@ -755,7 +745,7 @@ export class Installers {
     embed,
     extensionsService,
     ampdoc,
-    extensionIds,
+    extensions,
     preinstallCallback,
     opt_installComplete
   ) {
@@ -763,6 +753,9 @@ export class Installers {
     const parentWin = toWin(childWin.frameElement.ownerDocument.defaultView);
     setParentWindow(childWin, parentWin);
     const getDelayPromise = getDelayPromiseProducer();
+    // TODO(#33020): remove this when we pass full extensions object
+    // to installation service
+    const extensionIds = extensions.map(({extensionId}) => extensionId);
 
     return getDelayPromise(undefined)
       .then(() => {
diff --git a/test/unit/test-friendly-iframe-embed.js b/test/unit/test-friendly-iframe-embed.js
index ec5def1583d6..396fba7da2b6 100644
--- a/test/unit/test-friendly-iframe-embed.js
+++ b/test/unit/test-friendly-iframe-embed.js
@@ -111,6 +111,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
     const embedPromise = installFriendlyIframeEmbed(iframe, document.body, {
       url: 'https://acme.org/url1',
       html: '<a href="/url2"></a>',
+      extensions: [],
     });
 
     // Attributes set.
@@ -266,88 +267,6 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       });
   });
 
-  // TODO(#33020): Remove this test once `extensions` format is supported
-  // everywhere.
-  it('should create ampdoc and install extensions with extensionIds', () => {
-    // AmpDoc is created.
-    const ampdocSignals = new Signals();
-    let childWinForAmpDoc;
-    const ampdoc = {
-      get win() {
-        return childWinForAmpDoc;
-      },
-      getParent: () => env.ampdoc,
-      setReady: env.sandbox.spy(),
-      signals: () => ampdocSignals,
-      getHeadNode: () => childWinForAmpDoc.document.head,
-      setExtensionsKnown: env.sandbox.stub(),
-    };
-    ampdocServiceMock
-      .expects('installFieDoc')
-      .withExactArgs(
-        'https://acme.org/url1',
-        env.sandbox.match((arg) => {
-          // Match childWin argument.
-          childWinForAmpDoc = arg;
-          return true;
-        }),
-        env.sandbox.match((arg) => {
-          // Match options with no signals.
-          expect(arg && arg.signals).to.not.be.ok;
-          return true;
-        })
-      )
-      .returns(ampdoc)
-      .once();
-
-    // Extensions preloading have been requested.
-    extensionsMock
-      .expects('preloadExtension')
-      .withExactArgs('amp-test')
-      .returns(Promise.resolve())
-      .once();
-    extensionsMock
-      .expects('preinstallEmbed')
-      .withExactArgs(ampdoc, ['amp-test'])
-      .once();
-    extensionsMock
-      .expects('installExtensionsInDoc')
-      .withExactArgs(ampdoc, ['amp-test'])
-      .returns(Promise.resolve())
-      .once();
-
-    let renderCompleteResolver = null;
-    const renderCompletePromise = new Promise((resolve) => {
-      renderCompleteResolver = resolve;
-    });
-    env.sandbox
-      .stub(FriendlyIframeEmbed.prototype, 'whenRenderComplete')
-      .callsFake(() => renderCompletePromise);
-
-    const embedPromise = installFriendlyIframeEmbed(
-      iframe,
-      document.body,
-      {
-        url: 'https://acme.org/url1',
-        html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
-      },
-      preinstallCallback
-    );
-    return embedPromise
-      .then((embed) => {
-        expect(childWinForAmpDoc).to.equal(embed.win);
-        expect(ampdoc).to.equal(embed.ampdoc);
-        expect(installServicesStub).to.be.calledOnce.calledWith(ampdoc);
-        expect(ampdoc.setReady).to.not.be.called;
-        renderCompleteResolver();
-        return renderCompletePromise;
-      })
-      .then(() => {
-        expect(ampdoc.setReady).to.be.calledOnce;
-      });
-  });
-
   it('should create ampdoc and install extensions with host', () => {
     // host.
     const hostSignals = new Signals();
@@ -418,7 +337,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.org/url1',
         html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
+        extensions: [{extensionId: 'amp-test', extensionVersion: 'latest'}],
         host,
       },
       preinstallCallback
@@ -453,7 +372,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.org/url1',
         html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
+        extensions: [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       },
       preinstallCallback
     );
@@ -473,6 +392,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.org/url1',
         html: '<amp-test></amp-test>',
+        extensions: [],
       },
       (embedWin) => {
         registerServiceBuilderInEmbedWin(embedWin, 'c', function () {
@@ -528,7 +448,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.org/url1',
         html: '',
-        extensionIds: [],
+        extensions: [],
       },
       preinstallCallback
     );
@@ -552,7 +472,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.test/url1',
         html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
+        extensions: [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       },
       preinstallCallback
     );
@@ -567,7 +487,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.test/url1',
         html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
+        extensions: [{extensionId: 'amp-test', extensionVersion: 'latest'}],
         skipHtmlMerge: true,
       },
       preinstallCallback
@@ -632,7 +552,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       {
         url: 'https://acme.org/url1',
         html: '<amp-test></amp-test>',
-        extensionIds: ['amp-test'],
+        extensions: [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       },
       preinstallCallback
     );
@@ -746,6 +666,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
     await installFriendlyIframeEmbed(iframe, document.body, {
       url: 'https://acme.org/url1',
       html: '<a id="a1"></a>',
+      extensions: [],
     });
 
     expect(mutateSpy).to.not.be.called;
@@ -963,6 +884,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       const embedPromise = installFriendlyIframeEmbed(iframe, document.body, {
         url: 'https://acme.org/url1',
         html: '<a id="a1"></a>',
+        extensions: [],
       });
       return embedPromise.then(() => {
         expect(iframe.contentDocument.getElementById('a1')).to.be.ok;
@@ -974,6 +896,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       const embedPromise = installFriendlyIframeEmbed(iframe, document.body, {
         url: 'https://acme.org/url1',
         html: '<a id="a1"></a>',
+        extensions: [],
       });
       return embedPromise.then(() => {
         expect(iframe.contentDocument.getElementById('a1')).to.be.ok;
@@ -984,6 +907,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       const embedPromise = installFriendlyIframeEmbed(iframe, document.body, {
         url: 'https://acme.org/url1',
         html: '<a id="a1"></a>',
+        extensions: [],
       });
       return embedPromise.then((embed) => {
         return embed.whenWindowLoaded();
@@ -995,6 +919,7 @@ describes.realWin('friendly-iframe-embed', {amp: true}, (env) => {
       const embedPromise = installFriendlyIframeEmbed(iframe, document.body, {
         url: 'https://acme.org/url1',
         html: '<a id="a1"></a>',
+        extensions: [],
       });
       return embedPromise.then((embed) => {
         return embed.whenWindowLoaded();
@@ -1458,7 +1383,7 @@ describes.realWin('installExtensionsInEmbed', {amp: true}, (env) => {
       fie,
       extensions,
       ampdoc,
-      ['amp-test'],
+      [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       null,
       installComplete
     );
@@ -1541,7 +1466,7 @@ describes.realWin('installExtensionsInEmbed', {amp: true}, (env) => {
       fie,
       extensions,
       ampdoc,
-      ['amp-test'],
+      [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       null,
       installComplete
     );
@@ -1572,7 +1497,7 @@ describes.realWin('installExtensionsInEmbed', {amp: true}, (env) => {
       fie,
       extensions,
       ampdoc,
-      ['amp-test'],
+      [{extensionId: 'amp-test', extensionVersion: 'latest'}],
       function (winArg, ampdocArg) {
         expect(winArg).to.equal(iframeWin);
         expect(ampdocArg).to.equal(ampdoc);