faq: Add note about IMS domains

Author: jpds

static/faq.html

@@ -1114,6 +1114,11 @@ <h3><a href="#default-connections">What kind of connections do the OS and bundle
                             <p>DNS resolution for other connections involving connections to the
                             network / user provided DNS resolvers</p>
                         </li>
+                        <li>
+                            <p>Connections are made to the IP Multimedia Subsystem (IMS), when using
+                            Voice over LTE or WiFi calling (VoWIFI), this involves connections to
+                            <code>3gppnetwork.org</code> subdomains.</p>
+                        </li>
                     </ul>
 
                     <p>Other Vanadium browser connections are initiated by the user such as the