<string id="CreateMasterPassword_Explain">If false, removes access to create a master password.</string>
       <string id="DisableAppUpdate">Disable Update</string>
       <string id="DisableAppUpdate_Explain">Prevent the browser from updating.</string>
+      <string id="DisableBuiltinPDFViewer">Disable Builtin PDF Viewer</string>
+      <string id="DisableBuiltinPDFViewer_Explain">Disables PDF.js, which displays PDFs within Firefox.</string>
       <string id="DisableDeveloperTools">Disable Developer Tools</string>
       <string id="DisableDeveloperTools_Explain">Prevents access to developer tools.</string>
       <string id="DisableFirefoxAccounts">Disable Firefox Accounts</string>
 
         <decimal value="0"/>
       </disabledValue>
     </policy>
+    <policy name="DisableBuiltinPDFViewer" class="Both" displayName="$(string.DisableBuiltinPDFViewer)" explainText="$(string.DisableBuiltinPDFViewer_Explain)" key="Software\Policies\Mozilla\Firefox" valueName="DisableBuiltinPDFViewer">
+      <parentCategory ref="firefox"/>
+      <supportedOn ref="SUPPORTED_WINXPSP2"/>
+      <enabledValue>
+        <decimal value="1"/>
+      </enabledValue>
+      <disabledValue>
+        <decimal value="0"/>
+      </disabledValue>
+    </policy>
     <policy name="DisableDeveloperTools" class="Both" displayName="$(string.DisableDeveloperTools)" explainText="$(string.DisableDeveloperTools_Explain)" key="Software\Policies\Mozilla\Firefox" valueName="DisableDeveloperTools">
       <parentCategory ref="firefox"/>
       <supportedOn ref="SUPPORTED_WINXPSP2"/>