diff --git a/config/default.nix b/config/default.nix
index 7c31f67..691912d 100644
--- a/config/default.nix
+++ b/config/default.nix
@@ -1,6 +1,7 @@
 { config, lib, ... }:
 
 let
+  # https://github.com/NixOS/nixpkgs/pull/206965
   concatMapAttrsRecursive = with lib; f: flip pipe [ (mapAttrs f) attrValues (foldl' recursiveUpdate { }) ];
 in
 {