diff --git a/pkgs/top-level/config.nix b/pkgs/top-level/config.nix
index 701d44cd2605..f2066315efb5 100644
--- a/pkgs/top-level/config.nix
+++ b/pkgs/top-level/config.nix
@@ -433,7 +433,6 @@ let
         The intended use is to allow URL rewriting to insert company-internal mirrors, or work around company firewalls and similar network restrictions.
       '';
       default = null;
-      defaultText = literalExpression "(url: url)";
       example = literalExpression ''
         {
           # Use Nix like it's 2024! ;-)