diff --git a/pkgs/by-name/pd/pdfium-binaries/package.nix b/pkgs/by-name/pd/pdfium-binaries/package.nix
index 95202c7ff11b..8f4394c11416 100644
--- a/pkgs/by-name/pd/pdfium-binaries/package.nix
+++ b/pkgs/by-name/pd/pdfium-binaries/package.nix
@@ -5,6 +5,7 @@
   python3Packages,
 }:
 let
+  # also update rev of headers in python3Packages.pypdfium2
   version = "6968";
   src =
     let