diff --git a/web/app.js b/web/app.js
index 2af3a511e..5f4cc827c 100644
--- a/web/app.js
+++ b/web/app.js
@@ -824,8 +824,10 @@ const PDFViewerApplication = {
   async close() {
     this._unblockDocumentLoadEvent();
 
-    const errorWrapper = this.appConfig.errorWrapper.container;
-    errorWrapper.hidden = true;
+    if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
+      const { container } = this.appConfig.errorWrapper;
+      container.hidden = true;
+    }
 
     if (!this.pdfLoadingTask) {
       return undefined;
@@ -1421,7 +1423,10 @@ const PDFViewerApplication = {
       pdfViewer.optionalContentConfigPromise.then(optionalContentConfig => {
         this.pdfLayerViewer.render({ optionalContentConfig, pdfDocument });
       });
-      if ("requestIdleCallback" in window) {
+      if (
+        (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
+        "requestIdleCallback" in window
+      ) {
         const callback = window.requestIdleCallback(
           () => {
             this._collectTelemetry(pdfDocument);
diff --git a/web/pdf_cursor_tools.js b/web/pdf_cursor_tools.js
index c55bf34bc..39cc532f7 100644
--- a/web/pdf_cursor_tools.js
+++ b/web/pdf_cursor_tools.js
@@ -129,8 +129,6 @@ class PDFCursorTools {
 
     this.eventBus._on("presentationmodechanged", evt => {
       switch (evt.state) {
-        case PresentationModeState.CHANGING:
-          break;
         case PresentationModeState.FULLSCREEN: {
           const previouslyActive = this.active;
 
diff --git a/web/viewer.html b/web/viewer.html
index 4f1d08091..c390ba62e 100644
--- a/web/viewer.html
+++ b/web/viewer.html
@@ -320,6 +320,7 @@ See https://github.com/adobe-type-tools/cmap-resources
           <div id="viewer" class="pdfViewer"></div>
         </div>
 
+<!--#if !MOZCENTRAL-->
         <div id="errorWrapper" hidden='true'>
           <div id="errorMessageLeft">
             <span id="errorMessage"></span>
@@ -338,6 +339,7 @@ See https://github.com/adobe-type-tools/cmap-resources
           <div class="clearBoth"></div>
           <textarea id="errorMoreInfo" hidden='true' readonly="readonly"></textarea>
         </div>
+<!--#endif-->
       </div> <!-- mainContainer -->
 
       <div id="overlayContainer" class="hidden">
diff --git a/web/viewer.js b/web/viewer.js
index b524d840e..8c8435660 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -61,6 +61,18 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("CHROME || GENERIC")) {
 }
 
 function getViewerConfiguration() {
+  let errorWrapper = null;
+  if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
+    errorWrapper = {
+      container: document.getElementById("errorWrapper"),
+      errorMessage: document.getElementById("errorMessage"),
+      closeButton: document.getElementById("errorClose"),
+      errorMoreInfo: document.getElementById("errorMoreInfo"),
+      moreInfoButton: document.getElementById("errorShowMore"),
+      lessInfoButton: document.getElementById("errorShowLess"),
+    };
+  }
+
   return {
     appContainer: document.body,
     mainContainer: document.getElementById("viewerContainer"),
@@ -177,14 +189,7 @@ function getViewerConfiguration() {
         linearized: document.getElementById("linearizedField"),
       },
     },
-    errorWrapper: {
-      container: document.getElementById("errorWrapper"),
-      errorMessage: document.getElementById("errorMessage"),
-      closeButton: document.getElementById("errorClose"),
-      errorMoreInfo: document.getElementById("errorMoreInfo"),
-      moreInfoButton: document.getElementById("errorShowMore"),
-      lessInfoButton: document.getElementById("errorShowLess"),
-    },
+    errorWrapper,
     printContainer: document.getElementById("printContainer"),
     openFileInputName: "fileInput",
     debuggerScriptPath: "./debugger.js",