diff --git a/README.md b/README.md
index 4cae0298..e9b9aece 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,6 @@
 # cpython-source-deps
 Source for packages that the cpython build process depends on
+
+It is currently expected that this will only be useful on Windows,
+and in any case you should never need to clone this repository
+unless you are updating its contents.