diff --git a/tests/default.nix b/tests/default.nix
index 02842fa..929458e 100644
--- a/tests/default.nix
+++ b/tests/default.nix
@@ -32,6 +32,8 @@
         ./module-allow-rebuild-in-vm.nix
         # For the VM node, and the in-VM configuration.nix
         ./dynix-vm-configuration.nix
+        # NOTE: if `dynix` is a package (which it usually is), then
+        # this is IFD.
         dynix.dynix
       ];