diff --git a/nixos/tests/docker-tools.nix b/nixos/tests/docker-tools.nix
index 09741858c82e..06100f9d7842 100644
--- a/nixos/tests/docker-tools.nix
+++ b/nixos/tests/docker-tools.nix
@@ -3,7 +3,7 @@
 import ./make-test-python.nix ({ pkgs, ... }:
 let
   # nixpkgs#214434: dockerTools.buildImage fails to unpack base images
-  # containing duplicate rootfs diffs when those duplicate tarballs
+  # containing duplicate layers when those duplicate tarballs
   # appear under the manifest's 'Layers'. Docker can generate images
   # like this even though dockerTools does not.
   repeatedLayerTestImage =