diff --git a/toolkit/modules/GMPExtractor.worker.js b/toolkit/modules/GMPExtractor.worker.js
index 2c10daaf5092..0890c0c07711 100644
--- a/toolkit/modules/GMPExtractor.worker.js
+++ b/toolkit/modules/GMPExtractor.worker.js
@@ -6,70 +6,92 @@
 
 const FILE_ENTRY = "201: ";
 
+async function readJarDirectory(jarPath, installToDirPath) {
+  let extractedPaths = [];
+  // Construct a jar URI from the file URI so we can use the JAR URI scheme
+  // handling to navigate inside the zip file.
+  let jarResponse = await fetch(jarPath);
+  let dirListing = await jarResponse.text();
+  let lines = dirListing.split("\n");
+  let reader = new FileReader();
+  for (let line of lines) {
+    if (!line.startsWith(FILE_ENTRY)) {
+      // Not a file entry, skip.
+      continue;
+    }
+    // code: entry size modified-time type
+    let lineSplits = line.split(" ");
+    let jarEntry = lineSplits[1];
+    let jarType = lineSplits[4];
+    // Descend into and flatten any subfolders.
+    if (jarType === "DIRECTORY") {
+      extractedPaths.push(
+        ...(await readJarDirectory(jarPath + jarEntry, installToDirPath))
+      );
+      continue;
+    }
+    let fileName = jarEntry.split("/").pop();
+    // Only keep the binaries and metadata files.
+    if (
+      !fileName.endsWith(".info") &&
+      !fileName.endsWith(".dll") &&
+      !fileName.endsWith(".dylib") &&
+      !fileName.endsWith(".sig") &&
+      !fileName.endsWith(".so") &&
+      !fileName.endsWith(".txt") &&
+      fileName !== "LICENSE" &&
+      fileName !== "manifest.json"
+    ) {
+      continue;
+    }
+    let filePath = jarPath + jarEntry;
+    let filePathResponse = await fetch(filePath);
+    let fileContents = await filePathResponse.blob();
+    let fileData = await new Promise(resolve => {
+      reader.onloadend = function () {
+        resolve(reader.result);
+      };
+      reader.readAsArrayBuffer(fileContents);
+    });
+    await IOUtils.makeDirectory(installToDirPath);
+    // Do not extract into directories. Extract all files to the same
+    // directory.
+    let destPath = PathUtils.join(installToDirPath, fileName);
+    await IOUtils.write(destPath, new Uint8Array(fileData), {
+      tmpPath: destPath + ".tmp",
+    });
+    // Ensure files are writable and executable. Otherwise, we may be
+    // unable to execute or uninstall them.
+    await IOUtils.setPermissions(destPath, 0o700);
+    if (IOUtils.delMacXAttr) {
+      // If we're on MacOS Firefox will add the quarantine xattr to files it
+      // downloads. In this case we want to clear that xattr so we can load
+      // the CDM.
+      try {
+        await IOUtils.delMacXAttr(destPath, "com.apple.quarantine");
+      } catch (e) {
+        // Failed to remove the attribute. This could be because the profile
+        // exists on a file system without xattr support.
+        //
+        // Don't fail the extraction here, as in this case it's likely we
+        // didn't set quarantine on these files in the first place.
+      }
+    }
+    extractedPaths.push(destPath);
+  }
+  return extractedPaths;
+}
+
 onmessage = async function (msg) {
   try {
-    let extractedPaths = [];
     // Construct a jar URI from the file URI so we can use the JAR URI scheme
     // handling to navigate inside the zip file.
     let jarPath = "jar:" + msg.data.zipURI + "!/";
-    let jarResponse = await fetch(jarPath);
-    let dirListing = await jarResponse.text();
-    let lines = dirListing.split("\n");
-    let reader = new FileReader();
-    for (let line of lines) {
-      if (!line.startsWith(FILE_ENTRY)) {
-        // Not a file entry, skip.
-        continue;
-      }
-      let lineSplits = line.split(" ");
-      let fileName = lineSplits[1];
-      // We don't need these types of files.
-      if (
-        fileName == "verified_contents.json" ||
-        fileName == "icon-128x128.png" ||
-        fileName.startsWith("_")
-      ) {
-        continue;
-      }
-      let filePath = jarPath + fileName;
-      let filePathResponse = await fetch(filePath);
-      let fileContents = await filePathResponse.blob();
-      let fileData = await new Promise(resolve => {
-        reader.onloadend = function () {
-          resolve(reader.result);
-        };
-        reader.readAsArrayBuffer(fileContents);
-      });
-      let installToDirPath = PathUtils.join(
-        await PathUtils.getProfileDir(),
-        ...msg.data.relativeInstallPath
-      );
-      await IOUtils.makeDirectory(installToDirPath);
-      // Do not extract into directories. Extract all files to the same
-      // directory.
-      let destPath = PathUtils.join(installToDirPath, fileName);
-      await IOUtils.write(destPath, new Uint8Array(fileData), {
-        tmpPath: destPath + ".tmp",
-      });
-      // Ensure files are writable and executable. Otherwise, we may be
-      // unable to execute or uninstall them.
-      await IOUtils.setPermissions(destPath, 0o700);
-      if (IOUtils.delMacXAttr) {
-        // If we're on MacOS Firefox will add the quarantine xattr to files it
-        // downloads. In this case we want to clear that xattr so we can load
-        // the CDM.
-        try {
-          await IOUtils.delMacXAttr(destPath, "com.apple.quarantine");
-        } catch (e) {
-          // Failed to remove the attribute. This could be because the profile
-          // exists on a file system without xattr support.
-          //
-          // Don't fail the extraction here, as in this case it's likely we
-          // didn't set quarantine on these files in the first place.
-        }
-      }
-      extractedPaths.push(destPath);
-    }
+    let installToDirPath = PathUtils.join(
+      await PathUtils.getProfileDir(),
+      ...msg.data.relativeInstallPath
+    );
+    let extractedPaths = await readJarDirectory(jarPath, installToDirPath);
     postMessage({
       result: "success",
       extractedPaths,