diff --git a/nixos/lib/ini.nix b/nixos/lib/ini.nix
index ab085c8b7999e472fa5cde9ba1810a742e7c8086..43f211b121fddcf0bfddbfa3a4e620667d2147b4 100644
--- a/nixos/lib/ini.nix
+++ b/nixos/lib/ini.nix
@@ -1,3 +1,5 @@
+# Functionality related to writing out ini syntax files (like Tahoe-LAFS'
+# tahoe.cfg).
 { pkgs ? import <nixpkgs> { } }:
 let lib = pkgs.lib;
 in rec {