diff --git a/extensions/firefox/update.rdf b/extensions/firefox/update.rdf
index 5cdfff5cb..e95b114b5 100644
--- a/extensions/firefox/update.rdf
+++ b/extensions/firefox/update.rdf
@@ -14,6 +14,7 @@
                 <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
                 <em:minVersion>6.0</em:minVersion>
                 <em:maxVersion>11.*</em:maxVersion>
+                <!-- Use the raw link so we we can use SSL. -->
                 <em:updateLink>https://github.com/mozilla/pdf.js/raw/gh-pages/extensions/firefox/pdf.js.xpi</em:updateLink>
               </RDF:Description>
             </em:targetApplication>