diff --git a/README.md b/README.md
index f792dd1..fbd43f9 100644
--- a/README.md
+++ b/README.md
@@ -92,6 +92,7 @@ firefox.settings.services.mozilla.com
 
 https://bugzilla.mozilla.org/show_bug.cgi?id=1598562#c13
 
+content-signature-2.cdn.mozilla.net
 
 safebrowsing.googleapis.com, safebrowsing.google.com, malware-error.mozilla.com, phish-error.mozilla.com and developers.google.com (safebrowsing is active and not changeable)