diff --git a/flake.nix b/flake.nix
index e01383f6..1ca8a4ef 100644
--- a/flake.nix
+++ b/flake.nix
@@ -66,6 +66,7 @@
           "-DCMAKE_BUILD_TYPE=RelWithDebInfo"
 
           "-DFETCHCONTENT_SOURCE_DIR_JSON=${nlohmann-json}" # we care about the version
+          # TODO: use package instead
           "-DFETCHCONTENT_SOURCE_DIR_ZSTD=${pkgs.zstd.src}" # we dont care about the version (we use 1.4.x features)
         ];