src/display/node_utils.js

@@ -67,13 +67,6 @@ if (isNodeJS) {
         warn("Cannot polyfill `Path2D`, rendering may be broken.");
       }
     }
-    if (!globalThis.navigator?.language) {
-      globalThis.navigator = {
-        language: "en-US",
-        platform: "",
-        userAgent: "",
-      };
-    }
   }
 }
 

src/shared/util.js

@@ -643,6 +643,12 @@ class FeatureTest {
   }
 
   static get platform() {
+    if (
+      (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
+      (typeof navigator !== "undefined" &&
+        typeof navigator?.platform === "string" &&
+        typeof navigator?.userAgent === "string")
+    ) {
       const { platform, userAgent } = navigator;
 
       return shadow(this, "platform", {
@@ -655,6 +661,14 @@ class FeatureTest {
           userAgent.includes("Firefox"),
       });
     }
+    return shadow(this, "platform", {
+      isAndroid: false,
+      isLinux: false,
+      isMac: false,
+      isWindows: false,
+      isFirefox: false,
+    });
+  }
 
   static get isCSSRoundSupported() {
     return shadow(

web/app_options.js

@@ -19,16 +19,13 @@ if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
   if (
     typeof PDFJSDev !== "undefined" &&
     PDFJSDev.test("LIB") &&
-    !globalThis.navigator?.language
+    typeof navigator === "undefined"
   ) {
-    globalThis.navigator = {
+    globalThis.navigator = Object.create(null);
-      language: "en-US",
-      maxTouchPoints: 1,
-      platform: "",
-      userAgent: "",
-    };
   }
-  const { maxTouchPoints, platform, userAgent } = navigator;
+  const userAgent = navigator.userAgent || "";
+  const platform = navigator.platform || "";
+  const maxTouchPoints = navigator.maxTouchPoints || 1;
 
   const isAndroid = /Android/.test(userAgent);
   const isIOS =