diff --git a/domains/cert/pinning-test/index.html b/domains/cert/pinning-test/index.html
index c802f6af..88949dc9 100644
--- a/domains/cert/pinning-test/index.html
+++ b/domains/cert/pinning-test/index.html
@@ -12,5 +12,6 @@ <h1>
 </div>
 
 <div id="footer">
-  This site is preloaded with a bad HPKP pin starting in Chrome 48.
+    <div style="font-size: 2.5vw">This site is preloaded with a bad <a href="https://en.wikipedia.org/wiki/HTTP_Public_Key_Pinning">HPKP</a> pin starting in Chrome 48 and Firefox 44.</div>
+    <div style="font-size: 2.5vw">Pinning is disabled in the Opera builds.</div>
 </div>