diff --git a/etcnixos/vr.nix b/etcnixos/vr.nix
index 55327b0..7a3253f 100644
--- a/etcnixos/vr.nix
+++ b/etcnixos/vr.nix
@@ -15,6 +15,7 @@
     openFirewall = true;
 
     package = (
+      # https://github.com/NixOS/nixpkgs/pull/391367
       pkgs.wivrn.overrideAttrs (old: {
         cmakeFlags = old.cmakeFlags ++ [
           (lib.cmakeFeature "OPENCOMPOSITE_SEARCH_PATH" "${pkgs.opencomposite}/lib/opencomposite")