diff --git a/pkgs/by-name/li/libpkgconf/package.nix b/pkgs/by-name/li/libpkgconf/package.nix
index 0279b301f7c4..82685483cd77 100644
--- a/pkgs/by-name/li/libpkgconf/package.nix
+++ b/pkgs/by-name/li/libpkgconf/package.nix
@@ -14,6 +14,7 @@ stdenv.mkDerivation (finalAttrs: {
   pname = "pkgconf";
   version = "2.5.1";
 
+  # fetchFromGitHub isn't used because it's unavailable during bootstrapping
   src = fetchurl {
     url = "https://github.com/pkgconf/pkgconf/archive/refs/tags/pkgconf-${finalAttrs.version}.tar.gz";
     hash = "sha256-eXIbrcrRmH3q2cNgnrSHerm1iCHAa9rLgk8siJfBHyo=";