diff --git a/src/bin/gcc-shim.rs b/src/bin/gcc-shim.rs
index e5b53725..f0d219f4 100644
--- a/src/bin/gcc-shim.rs
+++ b/src/bin/gcc-shim.rs
@@ -1,3 +1,6 @@
+//! This bin target is only used for this crate's tests.
+//! It is not intended for users and is not published with the library code to crates.io.
+
 #![cfg_attr(test, allow(dead_code))]
 
 use std::env;