diff --git a/README.md b/README.md
index 90729f3b..0481934f 100644
--- a/README.md
+++ b/README.md
@@ -89,6 +89,9 @@ in the documentation for more information.
 
 GLFW itself depends only on the headers and libraries for your window system.
 
+The (experimental) Wayland backend also depends on the `extra-cmake-modules`
+package, which is used to generated Wayland protocol headers.
+
 The examples and test programs depend on a number of tiny libraries.  These are
 located in the `deps/` directory.