diff --git a/Appendix-B:-Firefox-Add-ons.md b/Appendix-B:-Firefox-Add-ons.md
index 0663672..a628e13 100644
--- a/Appendix-B:-Firefox-Add-ons.md
+++ b/Appendix-B:-Firefox-Add-ons.md
@@ -36,6 +36,8 @@ These are all, where applicable, best configured to `deny-all` and whitelist.
   * Configurable toggle buttons for JS, ~~Java~~, Flash, images and more. Suggest you don't use/enable anything that will conflict, such as the Cookies toggle.
 * :pushpin: :triangular_flag_on_post: [Smart Referer](https://addons.mozilla.org/en-US/firefox/addon/smart-referer/)
   * [WebExtension](https://github.com/meh/smart-referer/tree/wext) under development
+* [SSleuth](https://addons.mozilla.org/en-US/firefox/addon/ssleuth/) | [GitHub](https://github.com/sibiantony/ssleuth)
+   * Visual urlbar color/rating and one-click information on ciphers, PFS, SSL/TLS and CAs
 
 <sup>1</sup> Don't use multiple cookie add-ons