added firefox

Author: showipintbri

docs/firefox/index.md

@@ -0,0 +1,8 @@
+# Firefox
+
+## Disable ECH (Encrypted Client Hello)
+  1. Navigate to "about:config" in the URL bar.
+  2. In the configuration search bar enter: "ech"
+  3. Locate these 2 items and change them to "false":
+    - network.dns.echconfig.enabled
+    - network.dns.http3_echconfig.enabled