diff --git a/index.bs b/index.bs
index df3361633..8f661fcc4 100644
--- a/index.bs
+++ b/index.bs
@@ -4456,6 +4456,12 @@ Of the extended attributes defined in this specification, only the [{{Exposed}}]
 
 <h3 id="idl-modules">Modules</h3>
 
+<p class="advisement">
+This feature is a work in progress. Please
+<a href="https://github.com/heycam/webidl/issues/new?title=Using%20modules">file an issue</a>
+before using it.
+</p>
+
 A <dfn id="dfn-module" export>module</dfn> is a structure that exposes a collection of
 [=interfaces=], [=read only=] [=regular attributes=], and [=regular operations=] as a logical unit.
 A [=module=] has a <dfn for=module>specifier</dfn> that uniquely identifies it.