diff --git a/h5bp/web_performance/cache-control.conf b/h5bp/web_performance/cache-control.conf
index ad6506c..9513716 100644
--- a/h5bp/web_performance/cache-control.conf
+++ b/h5bp/web_performance/cache-control.conf
@@ -24,11 +24,13 @@
 #     directives meanings is highly recommended. A resource with `public` will
 #     be cached by shared caches like CDN, even if a user session is active.
 #
-# (*) The directive `no-cache` is defined by Nginx `expires` when set on
-#     `epoch`. This ensure a correct value enforcement whenever `Cache-Control`
-#     configuration is used or not.
-#     To avoid value duplication on `Cache-Control`, the directive is skipped
-#     here.
+# (*) To avoid duplication of the directive `no-cache` on `Cache-Control`,
+#     the value is skipped here.
+#     The directive `no-cache` is already defined by Nginx `expires` when set
+#     to `epoch`. This ensure a correct value enforcement whenever cache
+#     control configuration is used or not.
+#     Cache expiration configuration `expires` is described in the file
+#     h5bp/web_performance/cache_expiration.conf.
 #
 # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
 # https://www.rfc-editor.org/rfc/rfc9111.html