diff --git a/l10n/en-US/viewer.ftl b/l10n/en-US/viewer.ftl
index a0106b506..2193f51c6 100644
--- a/l10n/en-US/viewer.ftl
+++ b/l10n/en-US/viewer.ftl
@@ -218,11 +218,13 @@ pdfjs-additional-layers = Additional Layers
 
 # Variables:
 #   $page (Number) - the page number
-pdfjs-thumb-page-title = Page { $page }
+pdfjs-thumb-page-title =
+    .title = Page { $page }
 
 # Variables:
 #   $page (Number) - the page number
-pdfjs-thumb-page-canvas = Thumbnail of Page { $page }
+pdfjs-thumb-page-canvas =
+    .aria-label = Thumbnail of Page { $page }
 
 ## Find panel button title and messages
 
@@ -276,7 +278,8 @@ pdfjs-page-scale-percent = { $scale }%
 
 # Variables:
 #   $page (Number) - the page number
-pdfjs-page-landmark = Page { $page }
+pdfjs-page-landmark =
+    .aria-label = Page { $page }
 
 ## Loading indicator messages
 
diff --git a/src/display/annotation_layer.js b/src/display/annotation_layer.js
index 49651d7eb..d00863d70 100644
--- a/src/display/annotation_layer.js
+++ b/src/display/annotation_layer.js
@@ -983,8 +983,11 @@ class TextAnnotationElement extends AnnotationElement {
       "annotation-" +
       this.data.name.toLowerCase() +
       ".svg";
-    image.dataset.l10nId = "pdfjs-text-annotation-type";
-    image.dataset.l10nArgs = JSON.stringify({ type: this.data.name });
+    image.setAttribute("data-l10n-id", "pdfjs-text-annotation-type");
+    image.setAttribute(
+      "data-l10n-args",
+      JSON.stringify({ type: this.data.name })
+    );
 
     if (!this.data.popupRef && this.hasPopupData) {
       this._createPopup();
@@ -2158,11 +2161,17 @@ class PopupElement {
     if (this.#dateObj) {
       const modificationDate = document.createElement("span");
       modificationDate.classList.add("popupDate");
-      modificationDate.dataset.l10nId = "pdfjs-annotation-date-string";
-      modificationDate.dataset.l10nArgs = JSON.stringify({
-        date: this.#dateObj.toLocaleDateString(),
-        time: this.#dateObj.toLocaleTimeString(),
-      });
+      modificationDate.setAttribute(
+        "data-l10n-id",
+        "pdfjs-annotation-date-string"
+      );
+      modificationDate.setAttribute(
+        "data-l10n-args",
+        JSON.stringify({
+          date: this.#dateObj.toLocaleDateString(),
+          time: this.#dateObj.toLocaleTimeString(),
+        })
+      );
       header.append(modificationDate);
     }
 
@@ -2889,14 +2898,12 @@ class AnnotationLayer {
     div,
     accessibilityManager,
     annotationCanvasMap,
-    l10n,
     page,
     viewport,
   }) {
     this.div = div;
     this.#accessibilityManager = accessibilityManager;
     this.#annotationCanvasMap = annotationCanvasMap;
-    this.l10n = l10n;
     this.page = page;
     this.viewport = viewport;
     this.zIndex = 0;
diff --git a/test/driver.js b/test/driver.js
index bc4c5f693..e91ee9cc9 100644
--- a/test/driver.js
+++ b/test/driver.js
@@ -25,8 +25,7 @@ const {
   shadow,
   XfaLayer,
 } = pdfjsLib;
-const { GenericL10n, NullL10n, parseQueryString, SimpleLinkService } =
-  pdfjsViewer;
+const { GenericL10n, parseQueryString, SimpleLinkService } = pdfjsViewer;
 
 const WAITING_TIME = 100; // ms
 const CMAP_URL = "/build/generic/web/cmaps/";
@@ -215,8 +214,7 @@ class Rasterize {
     annotationCanvasMap,
     page,
     imageResourcesPath,
-    renderForms = false,
-    l10n = NullL10n
+    renderForms = false
   ) {
     try {
       const { svg, foreignObject, style, div } = this.createContainer(viewport);
@@ -248,7 +246,6 @@ class Rasterize {
         div,
         annotationCanvasMap: annotationImageMap,
         page,
-        l10n,
         viewport: annotationViewport,
       });
       await annotationLayer.render(parameters);
@@ -356,6 +353,8 @@ class Driver {
     // Configure the global worker options.
     GlobalWorkerOptions.workerSrc = WORKER_SRC;
 
+    // We only need to initialize the `L10n`-instance here, since translation is
+    // triggered by a `MutationObserver`; see e.g. `Rasterize.annotationLayer`.
     this._l10n = new GenericL10n(VIEWER_LOCALE);
 
     // Set the passed options
@@ -879,8 +878,7 @@ class Driver {
                       annotationCanvasMap,
                       page,
                       IMAGE_RESOURCES_PATH,
-                      renderForms,
-                      this._l10n
+                      renderForms
                     ).then(() => {
                       completeRender(false);
                     });
diff --git a/web/annotation_layer_builder.js b/web/annotation_layer_builder.js
index 43cb1d9c5..ca0c824d3 100644
--- a/web/annotation_layer_builder.js
+++ b/web/annotation_layer_builder.js
@@ -19,13 +19,11 @@
 // eslint-disable-next-line max-len
 /** @typedef {import("../src/display/annotation_storage").AnnotationStorage} AnnotationStorage */
 /** @typedef {import("./interfaces").IDownloadManager} IDownloadManager */
-/** @typedef {import("./interfaces").IL10n} IL10n */
 /** @typedef {import("./interfaces").IPDFLinkService} IPDFLinkService */
 // eslint-disable-next-line max-len
 /** @typedef {import("./text_accessibility.js").TextAccessibilityManager} TextAccessibilityManager */
 
 import { AnnotationLayer } from "pdfjs-lib";
-import { NullL10n } from "web-l10n_utils";
 import { PresentationModeState } from "./ui_utils.js";
 
 /**
@@ -38,7 +36,6 @@ import { PresentationModeState } from "./ui_utils.js";
  * @property {boolean} renderForms
  * @property {IPDFLinkService} linkService
  * @property {IDownloadManager} [downloadManager]
- * @property {IL10n} l10n - Localization service.
  * @property {boolean} [enableScripting]
  * @property {Promise<boolean>} [hasJSActionsPromise]
  * @property {Promise<Object<string, Array<Object>> | null>}
@@ -61,7 +58,6 @@ class AnnotationLayerBuilder {
     annotationStorage = null,
     imageResourcesPath = "",
     renderForms = true,
-    l10n = NullL10n,
     enableScripting = false,
     hasJSActionsPromise = null,
     fieldObjectsPromise = null,
@@ -74,7 +70,6 @@ class AnnotationLayerBuilder {
     this.downloadManager = downloadManager;
     this.imageResourcesPath = imageResourcesPath;
     this.renderForms = renderForms;
-    this.l10n = l10n;
     this.annotationStorage = annotationStorage;
     this.enableScripting = enableScripting;
     this._hasJSActionsPromise = hasJSActionsPromise || Promise.resolve(false);
@@ -131,7 +126,6 @@ class AnnotationLayerBuilder {
       div,
       accessibilityManager: this._accessibilityManager,
       annotationCanvasMap: this._annotationCanvasMap,
-      l10n: this.l10n,
       page: this.pdfPage,
       viewport: viewport.clone({ dontFlip: true }),
     });
diff --git a/web/app.js b/web/app.js
index 8c69dc245..216a49b04 100644
--- a/web/app.js
+++ b/web/app.js
@@ -521,7 +521,6 @@ const PDFViewerApplication = {
         eventBus,
         renderingQueue: pdfRenderingQueue,
         linkService: pdfLinkService,
-        l10n,
         pageColors,
       });
       pdfRenderingQueue.setThumbnailViewer(this.pdfThumbnailViewer);
@@ -538,7 +537,7 @@ const PDFViewerApplication = {
     }
 
     if (!this.supportsIntegratedFind && appConfig.findBar) {
-      this.findBar = new PDFFindBar(appConfig.findBar, eventBus, l10n);
+      this.findBar = new PDFFindBar(appConfig.findBar, eventBus);
     }
 
     if (appConfig.annotationEditorParams) {
@@ -587,11 +586,10 @@ const PDFViewerApplication = {
         this.toolbar = new Toolbar(
           appConfig.toolbar,
           eventBus,
-          l10n,
           await this._nimbusDataPromise
         );
       } else {
-        this.toolbar = new Toolbar(appConfig.toolbar, eventBus, l10n);
+        this.toolbar = new Toolbar(appConfig.toolbar, eventBus);
       }
     }
 
@@ -617,7 +615,6 @@ const PDFViewerApplication = {
       this.passwordPrompt = new PasswordPrompt(
         appConfig.passwordOverlay,
         this.overlayManager,
-        l10n,
         this.isViewerEmbedded
       );
     }
@@ -643,7 +640,6 @@ const PDFViewerApplication = {
       this.pdfLayerViewer = new PDFLayerViewer({
         container: appConfig.sidebar.layersView,
         eventBus,
-        l10n,
       });
     }
 
@@ -1848,8 +1844,7 @@ const PDFViewerApplication = {
       printContainer,
       printResolution,
       optionalContentConfigPromise,
-      this._printAnnotationStoragePromise,
-      this.l10n
+      this._printAnnotationStoragePromise
     );
     this.printService = printService;
     this.forceRendering();
diff --git a/web/l10n_utils.js b/web/l10n_utils.js
index 92e17b5f0..940c68c8f 100644
--- a/web/l10n_utils.js
+++ b/web/l10n_utils.js
@@ -18,13 +18,12 @@
 import { FluentBundle, FluentResource } from "fluent-bundle";
 import { DOMLocalization } from "fluent-dom";
 import { L10n } from "./l10n.js";
+import { shadow } from "pdfjs-lib";
 
 /**
  * @implements {IL10n}
  */
 class ConstL10n extends L10n {
-  static #instance;
-
   constructor(lang) {
     super({ lang });
     this.setL10n(
@@ -51,7 +50,7 @@ class ConstL10n extends L10n {
   }
 
   static get instance() {
-    return (this.#instance ||= new ConstL10n("en-US"));
+    return shadow(this, "instance", new ConstL10n("en-US"));
   }
 }
 
diff --git a/web/password_prompt.js b/web/password_prompt.js
index e3e8b01d1..864307152 100644
--- a/web/password_prompt.js
+++ b/web/password_prompt.js
@@ -37,18 +37,16 @@ class PasswordPrompt {
   /**
    * @param {PasswordPromptOptions} options
    * @param {OverlayManager} overlayManager - Manager for the viewer overlays.
-   * @param {IL10n} l10n - Localization service.
    * @param {boolean} [isViewerEmbedded] - If the viewer is embedded, in e.g.
    *   an <iframe> or an <object>. The default value is `false`.
    */
-  constructor(options, overlayManager, l10n, isViewerEmbedded = false) {
+  constructor(options, overlayManager, isViewerEmbedded = false) {
     this.dialog = options.dialog;
     this.label = options.label;
     this.input = options.input;
     this.submitButton = options.submitButton;
     this.cancelButton = options.cancelButton;
     this.overlayManager = overlayManager;
-    this.l10n = l10n;
     this._isViewerEmbedded = isViewerEmbedded;
 
     // Attach the event listeners.
@@ -84,7 +82,8 @@ class PasswordPrompt {
     if (!this._isViewerEmbedded || passwordIncorrect) {
       this.input.focus();
     }
-    this.label.textContent = await this.l10n.get(
+    this.label.setAttribute(
+      "data-l10n-id",
       `pdfjs-password-${passwordIncorrect ? "invalid" : "label"}`
     );
   }
diff --git a/web/pdf_find_bar.js b/web/pdf_find_bar.js
index b1dfd5697..a2b0f5477 100644
--- a/web/pdf_find_bar.js
+++ b/web/pdf_find_bar.js
@@ -27,7 +27,7 @@ const MATCHES_COUNT_LIMIT = 1000;
 class PDFFindBar {
   #resizeObserver = new ResizeObserver(this.#resizeObserverCallback.bind(this));
 
-  constructor(options, eventBus, l10n) {
+  constructor(options, eventBus) {
     this.opened = false;
 
     this.bar = options.bar;
@@ -42,7 +42,6 @@ class PDFFindBar {
     this.findPreviousButton = options.findPreviousButton;
     this.findNextButton = options.findNextButton;
     this.eventBus = eventBus;
-    this.l10n = l10n;
 
     // Add event listeners to the DOM elements.
     this.toggleButton.addEventListener("click", () => {
@@ -109,8 +108,9 @@ class PDFFindBar {
   }
 
   updateUIState(state, previous, matchesCount) {
-    let findMsg = Promise.resolve("");
-    let status = "";
+    const { findField, findMsg } = this;
+    let findMsgId = "",
+      status = "";
 
     switch (state) {
       case FindState.FOUND:
@@ -119,39 +119,46 @@ class PDFFindBar {
         status = "pending";
         break;
       case FindState.NOT_FOUND:
-        findMsg = this.l10n.get("pdfjs-find-not-found");
+        findMsgId = "pdfjs-find-not-found";
         status = "notFound";
         break;
       case FindState.WRAPPED:
-        findMsg = this.l10n.get(
-          `pdfjs-find-reached-${previous ? "top" : "bottom"}`
-        );
+        findMsgId = `pdfjs-find-reached-${previous ? "top" : "bottom"}`;
         break;
     }
-    this.findField.setAttribute("data-status", status);
-    this.findField.setAttribute("aria-invalid", state === FindState.NOT_FOUND);
+    findField.setAttribute("data-status", status);
+    findField.setAttribute("aria-invalid", state === FindState.NOT_FOUND);
 
-    findMsg.then(msg => {
-      this.findMsg.setAttribute("data-status", status);
-      this.findMsg.textContent = msg;
-    });
+    findMsg.setAttribute("data-status", status);
+    if (findMsgId) {
+      findMsg.setAttribute("data-l10n-id", findMsgId);
+    } else {
+      findMsg.removeAttribute("data-l10n-id");
+      findMsg.textContent = "";
+    }
 
     this.updateResultsCount(matchesCount);
   }
 
   updateResultsCount({ current = 0, total = 0 } = {}) {
-    const limit = MATCHES_COUNT_LIMIT;
-    let matchCountMsg = Promise.resolve("");
+    const { findResultsCount } = this;
 
     if (total > 0) {
-      matchCountMsg =
-        total > limit
-          ? this.l10n.get("pdfjs-find-match-count-limit", { limit })
-          : this.l10n.get("pdfjs-find-match-count", { current, total });
+      const limit = MATCHES_COUNT_LIMIT,
+        isLimited = total > limit;
+
+      findResultsCount.setAttribute(
+        "data-l10n-id",
+        `pdfjs-find-match-count${isLimited ? "-limit" : ""}`
+      );
+      findResultsCount.setAttribute(
+        "data-l10n-args",
+        JSON.stringify(isLimited ? { limit } : { current, total })
+      );
+    } else {
+      findResultsCount.removeAttribute("data-l10n-id");
+      findResultsCount.textContent = "";
     }
-    matchCountMsg.then(msg => {
-      this.findResultsCount.textContent = msg;
-    });
   }
 
   open() {
diff --git a/web/pdf_layer_viewer.js b/web/pdf_layer_viewer.js
index 5387b0be8..6eb701ae8 100644
--- a/web/pdf_layer_viewer.js
+++ b/web/pdf_layer_viewer.js
@@ -19,7 +19,6 @@ import { BaseTreeViewer } from "./base_tree_viewer.js";
  * @typedef {Object} PDFLayerViewerOptions
  * @property {HTMLDivElement} container - The viewer element.
  * @property {EventBus} eventBus - The application event bus.
- * @property {IL10n} l10n - Localization service.
  */
 
 /**
@@ -32,7 +31,6 @@ import { BaseTreeViewer } from "./base_tree_viewer.js";
 class PDFLayerViewer extends BaseTreeViewer {
   constructor(options) {
     super(options);
-    this.l10n = options.l10n;
 
     this.eventBus._on("optionalcontentconfigchanged", evt => {
       this.#updateLayers(evt.promise);
@@ -89,7 +87,7 @@ class PDFLayerViewer extends BaseTreeViewer {
   /**
    * @private
    */
-  async _setNestedName(element, { name = null }) {
+  _setNestedName(element, { name = null }) {
     if (typeof name === "string") {
       element.textContent = this._normalizeTextContent(name);
       return;
diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index c8fea03ed..68e18a4a1 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -182,9 +182,8 @@ class PDFPageView {
     div.className = "page";
     div.setAttribute("data-page-number", this.id);
     div.setAttribute("role", "region");
-    this.l10n.get("pdfjs-page-landmark", { page: this.id }).then(msg => {
-      div.setAttribute("aria-label", msg);
-    });
+    div.setAttribute("data-l10n-id", "pdfjs-page-landmark");
+    div.setAttribute("data-l10n-args", JSON.stringify({ page: this.id }));
     this.div = div;
 
     this.#setDimensions();
@@ -878,7 +877,6 @@ class PDFPageView {
         renderForms: this.#annotationMode === AnnotationMode.ENABLE_FORMS,
         linkService,
         downloadManager,
-        l10n,
         enableScripting,
         hasJSActionsPromise,
         fieldObjectsPromise,
diff --git a/web/pdf_print_service.js b/web/pdf_print_service.js
index e12bd9f2e..845444573 100644
--- a/web/pdf_print_service.js
+++ b/web/pdf_print_service.js
@@ -69,8 +69,7 @@ class PDFPrintService {
     printContainer,
     printResolution,
     optionalContentConfigPromise = null,
-    printAnnotationStoragePromise = null,
-    l10n
+    printAnnotationStoragePromise = null
   ) {
     this.pdfDocument = pdfDocument;
     this.pagesOverview = pagesOverview;
@@ -80,7 +79,6 @@ class PDFPrintService {
       optionalContentConfigPromise || pdfDocument.getOptionalContentConfig();
     this._printAnnotationStoragePromise =
       printAnnotationStoragePromise || Promise.resolve();
-    this.l10n = l10n;
     this.currentPage = -1;
     // The temporary canvas where renderPage paints one page at a time.
     this.scratchCanvas = document.createElement("canvas");
@@ -151,12 +149,12 @@ class PDFPrintService {
     const renderNextPage = (resolve, reject) => {
       this.throwIfInactive();
       if (++this.currentPage >= pageCount) {
-        renderProgress(pageCount, pageCount, this.l10n);
+        renderProgress(pageCount, pageCount);
         resolve();
         return;
       }
       const index = this.currentPage;
-      renderProgress(index, pageCount, this.l10n);
+      renderProgress(index, pageCount);
       renderPage(
         this,
         this.pdfDocument,
@@ -288,7 +286,7 @@ function abort() {
   }
 }
 
-function renderProgress(index, total, l10n) {
+function renderProgress(index, total) {
   if (typeof PDFJSDev === "undefined" && window.isGECKOVIEW) {
     return;
   }
@@ -297,9 +295,7 @@ function renderProgress(index, total, l10n) {
   const progressBar = dialog.querySelector("progress");
   const progressPerc = dialog.querySelector(".relative-progress");
   progressBar.value = progress;
-  l10n.get("pdfjs-print-progress-percent", { progress }).then(msg => {
-    progressPerc.textContent = msg;
-  });
+  progressPerc.setAttribute("data-l10n-args", JSON.stringify({ progress }));
 }
 
 window.addEventListener(
@@ -368,8 +364,7 @@ PDFPrintServiceFactory.instance = {
     printContainer,
     printResolution,
     optionalContentConfigPromise,
-    printAnnotationStoragePromise,
-    l10n
+    printAnnotationStoragePromise
   ) {
     if (activeService) {
       throw new Error("The print service is created and active.");
@@ -380,8 +375,7 @@ PDFPrintServiceFactory.instance = {
       printContainer,
       printResolution,
       optionalContentConfigPromise,
-      printAnnotationStoragePromise,
-      l10n
+      printAnnotationStoragePromise
     );
     return activeService;
   },
diff --git a/web/pdf_sidebar.js b/web/pdf_sidebar.js
index 5096cd5c7..394c4e322 100644
--- a/web/pdf_sidebar.js
+++ b/web/pdf_sidebar.js
@@ -111,7 +111,6 @@ class PDFSidebar {
     this._currentOutlineItemButton = elements.currentOutlineItemButton;
 
     this.eventBus = eventBus;
-    this.l10n = l10n;
 
     this.#isRTL = l10n.getDirection() === "rtl";
     this.#addEventListeners();
diff --git a/web/pdf_thumbnail_view.js b/web/pdf_thumbnail_view.js
index cd3d1e8d8..67b0779bc 100644
--- a/web/pdf_thumbnail_view.js
+++ b/web/pdf_thumbnail_view.js
@@ -18,7 +18,6 @@
 // eslint-disable-next-line max-len
 /** @typedef {import("../src/display/display_utils").PageViewport} PageViewport */
 /** @typedef {import("./event_utils").EventBus} EventBus */
-/** @typedef {import("./interfaces").IL10n} IL10n */
 /** @typedef {import("./interfaces").IPDFLinkService} IPDFLinkService */
 /** @typedef {import("./interfaces").IRenderableView} IRenderableView */
 // eslint-disable-next-line max-len
@@ -42,7 +41,6 @@ const THUMBNAIL_WIDTH = 98; // px
  *   The default value is `null`.
  * @property {IPDFLinkService} linkService - The navigation/linking service.
  * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
- * @property {IL10n} l10n - Localization service.
  * @property {Object} [pageColors] - Overwrites background and foreground colors
  *   with user defined ones in order to improve readability in high contrast
  *   mode.
@@ -93,7 +91,6 @@ class PDFThumbnailView {
     optionalContentConfigPromise,
     linkService,
     renderingQueue,
-    l10n,
     pageColors,
   }) {
     this.id = id;
@@ -114,13 +111,11 @@ class PDFThumbnailView {
     this.renderTask = null;
     this.renderingState = RenderingStates.INITIAL;
     this.resume = null;
-    this.l10n = l10n;
 
     const anchor = document.createElement("a");
     anchor.href = linkService.getAnchorUrl("#page=" + id);
-    this._thumbPageTitle.then(msg => {
-      anchor.title = msg;
-    });
+    anchor.setAttribute("data-l10n-id", "pdfjs-thumb-page-title");
+    anchor.setAttribute("data-l10n-args", this.#pageL10nArgs);
     anchor.onclick = function () {
       linkService.goToPage(id);
       return false;
@@ -232,9 +227,8 @@ class PDFThumbnailView {
 
     const image = document.createElement("img");
     image.className = "thumbnailImage";
-    this._thumbPageCanvas.then(msg => {
-      image.setAttribute("aria-label", msg);
-    });
+    image.setAttribute("data-l10n-id", "pdfjs-thumb-page-canvas");
+    image.setAttribute("data-l10n-args", this.#pageL10nArgs);
     image.src = reducedCanvas.toDataURL();
     this.image = image;
 
@@ -423,16 +417,8 @@ class PDFThumbnailView {
     return canvas;
   }
 
-  get _thumbPageTitle() {
-    return this.l10n.get("pdfjs-thumb-page-title", {
-      page: this.pageLabel ?? this.id,
-    });
-  }
-
-  get _thumbPageCanvas() {
-    return this.l10n.get("pdfjs-thumb-page-canvas", {
-      page: this.pageLabel ?? this.id,
-    });
+  get #pageL10nArgs() {
+    return JSON.stringify({ page: this.pageLabel ?? this.id });
   }
 
   /**
@@ -441,17 +427,12 @@ class PDFThumbnailView {
   setPageLabel(label) {
     this.pageLabel = typeof label === "string" ? label : null;
 
-    this._thumbPageTitle.then(msg => {
-      this.anchor.title = msg;
-    });
+    this.anchor.setAttribute("data-l10n-args", this.#pageL10nArgs);
 
     if (this.renderingState !== RenderingStates.FINISHED) {
       return;
     }
-
-    this._thumbPageCanvas.then(msg => {
-      this.image?.setAttribute("aria-label", msg);
-    });
+    this.image?.setAttribute("data-l10n-args", this.#pageL10nArgs);
   }
 }
 
diff --git a/web/pdf_thumbnail_viewer.js b/web/pdf_thumbnail_viewer.js
index a53b8ca08..a16d84c4f 100644
--- a/web/pdf_thumbnail_viewer.js
+++ b/web/pdf_thumbnail_viewer.js
@@ -16,7 +16,6 @@
 /** @typedef {import("../src/display/api").PDFDocumentProxy} PDFDocumentProxy */
 /** @typedef {import("../src/display/api").PDFPageProxy} PDFPageProxy */
 /** @typedef {import("./event_utils").EventBus} EventBus */
-/** @typedef {import("./interfaces").IL10n} IL10n */
 /** @typedef {import("./interfaces").IPDFLinkService} IPDFLinkService */
 // eslint-disable-next-line max-len
 /** @typedef {import("./pdf_rendering_queue").PDFRenderingQueue} PDFRenderingQueue */
@@ -40,7 +39,6 @@ const THUMBNAIL_SELECTED_CLASS = "selected";
  * @property {EventBus} eventBus - The application event bus.
  * @property {IPDFLinkService} linkService - The navigation/linking service.
  * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
- * @property {IL10n} l10n - Localization service.
  * @property {Object} [pageColors] - Overwrites background and foreground colors
  *   with user defined ones in order to improve readability in high contrast
  *   mode.
@@ -58,14 +56,12 @@ class PDFThumbnailViewer {
     eventBus,
     linkService,
     renderingQueue,
-    l10n,
     pageColors,
   }) {
     this.container = container;
     this.eventBus = eventBus;
     this.linkService = linkService;
     this.renderingQueue = renderingQueue;
-    this.l10n = l10n;
     this.pageColors = pageColors || null;
 
     this.scroll = watchScroll(this.container, this._scrollUpdated.bind(this));
@@ -209,7 +205,6 @@ class PDFThumbnailViewer {
             optionalContentConfigPromise,
             linkService: this.linkService,
             renderingQueue: this.renderingQueue,
-            l10n: this.l10n,
             pageColors: this.pageColors,
           });
           this._thumbnails.push(thumbnail);
diff --git a/web/toolbar-geckoview.js b/web/toolbar-geckoview.js
index 12cd77297..0d1ffab04 100644
--- a/web/toolbar-geckoview.js
+++ b/web/toolbar-geckoview.js
@@ -28,10 +28,9 @@ class Toolbar {
   /**
    * @param {ToolbarOptions} options
    * @param {EventBus} eventBus
-   * @param {IL10n} _l10n - Localization service.
    * @param {Object} nimbusData - Nimbus configuration.
    */
-  constructor(options, eventBus, _l10n, nimbusData) {
+  constructor(options, eventBus, nimbusData) {
     this.#eventBus = eventBus;
     const buttons = [
       {
diff --git a/web/toolbar.js b/web/toolbar.js
index 80567e96d..516cc096b 100644
--- a/web/toolbar.js
+++ b/web/toolbar.js
@@ -49,12 +49,10 @@ class Toolbar {
   /**
    * @param {ToolbarOptions} options
    * @param {EventBus} eventBus
-   * @param {IL10n} l10n - Localization service.
    */
-  constructor(options, eventBus, l10n) {
+  constructor(options, eventBus) {
     this.toolbar = options.container;
     this.eventBus = eventBus;
-    this.l10n = l10n;
     this.buttons = [
       { element: options.previous, eventName: "previouspage" },
       { element: options.next, eventName: "nextpage" },
@@ -252,22 +250,27 @@ class Toolbar {
     if (resetNumPages) {
       if (this.hasPageLabels) {
         items.pageNumber.type = "text";
+
+        items.numPages.setAttribute("data-l10n-id", "pdfjs-page-of-pages");
       } else {
         items.pageNumber.type = "number";
-        this.l10n.get("pdfjs-of-pages", { pagesCount }).then(msg => {
-          items.numPages.textContent = msg;
-        });
+
+        items.numPages.setAttribute("data-l10n-id", "pdfjs-of-pages");
+        items.numPages.setAttribute(
+          "data-l10n-args",
+          JSON.stringify({ pagesCount })
+        );
       }
       items.pageNumber.max = pagesCount;
     }
 
     if (this.hasPageLabels) {
       items.pageNumber.value = this.pageLabel;
-      this.l10n
-        .get("pdfjs-page-of-pages", { pageNumber, pagesCount })
-        .then(msg => {
-          items.numPages.textContent = msg;
-        });
+
+      items.numPages.setAttribute(
+        "data-l10n-args",
+        JSON.stringify({ pageNumber, pagesCount })
+      );
     } else {
       items.pageNumber.value = pageNumber;
     }
@@ -278,25 +281,24 @@ class Toolbar {
     items.zoomOut.disabled = pageScale <= MIN_SCALE;
     items.zoomIn.disabled = pageScale >= MAX_SCALE;
 
-    this.l10n
-      .get("pdfjs-page-scale-percent", {
-        scale: Math.round(pageScale * 10000) / 100,
-      })
-      .then(msg => {
-        let predefinedValueFound = false;
-        for (const option of items.scaleSelect.options) {
-          if (option.value !== pageScaleValue) {
-            option.selected = false;
-            continue;
-          }
-          option.selected = true;
-          predefinedValueFound = true;
-        }
-        if (!predefinedValueFound) {
-          items.customScaleOption.textContent = msg;
-          items.customScaleOption.selected = true;
-        }
-      });
+    let predefinedValueFound = false;
+    for (const option of items.scaleSelect.options) {
+      if (option.value !== pageScaleValue) {
+        option.selected = false;
+        continue;
+      }
+      option.selected = true;
+      predefinedValueFound = true;
+    }
+    if (!predefinedValueFound) {
+      items.customScaleOption.selected = true;
+      items.customScaleOption.setAttribute(
+        "data-l10n-args",
+        JSON.stringify({
+          scale: Math.round(pageScale * 10000) / 100,
+        })
+      );
+    }
   }
 
   updateLoadingIndicatorState(loading = false) {
diff --git a/web/viewer.html b/web/viewer.html
index 033355716..144f8de3f 100644
--- a/web/viewer.html
+++ b/web/viewer.html
@@ -379,7 +379,7 @@ See https://github.com/adobe-type-tools/cmap-resources
                     <option id="pageActualOption" title="" value="page-actual" data-l10n-id="pdfjs-page-scale-actual">Actual Size</option>
                     <option id="pageFitOption" title="" value="page-fit" data-l10n-id="pdfjs-page-scale-fit">Page Fit</option>
                     <option id="pageWidthOption" title="" value="page-width" data-l10n-id="pdfjs-page-scale-width">Page Width</option>
-                    <option id="customScaleOption" title="" value="custom" disabled="disabled" hidden="true"></option>
+                    <option id="customScaleOption" title="" value="custom" disabled="disabled" hidden="true" data-l10n-id="pdfjs-page-scale-percent" data-l10n-args='{ "scale": 0 }'>0%</option>
                     <option title="" value="0.5" data-l10n-id="pdfjs-page-scale-percent" data-l10n-args='{ "scale": 50 }'>50%</option>
                     <option title="" value="0.75" data-l10n-id="pdfjs-page-scale-percent" data-l10n-args='{ "scale": 75 }'>75%</option>
                     <option title="" value="1" data-l10n-id="pdfjs-page-scale-percent" data-l10n-args='{ "scale": 100 }'>100%</option>