diff --git a/nginx.tmpl b/nginx.tmpl
index f0cae0d..cb558e5 100644
--- a/nginx.tmpl
+++ b/nginx.tmpl
@@ -1,3 +1,5 @@
+# If we receive X-Forwarded-Proto, pass it through; otherwise, pass along the
+# scheme used to connect to this server
 map $http_x_forwarded_proto $proxy_x_forwarded_proto {
   default $http_x_forwarded_proto;
   ''      $scheme;