diff --git a/.cargo/config.toml b/.cargo/config.toml
index 81b02b327..69724fd30 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -3,3 +3,7 @@ runner = 'wasm-bindgen-test-runner'
 
 [target.'cfg(all(target_arch = "wasm32", target_os = "wasi"))']
 runner = 'wasmtime -W unknown-imports-trap=y'
+
+# This section needs to be last.
+# GitHub Actions modifies this section.
+[unstable]