diff --git a/README.md b/README.md
index 06cfd07..56457aa 100644
--- a/README.md
+++ b/README.md
@@ -105,3 +105,17 @@ programmatically, and because some flags are mutually exclusive.
 
 I may end up approximating this by checking in a hardcoded `init.el` with all
 (or at least most) currently-available flags enabled.
+
+### Some pins may not be applied
+
+Doom
+[mentions](https://github.com/doomemacs/doomemacs/blob/9620bb45ac4cd7b0274c497b2d9d93c4ad9364ee/modules/ui/treemacs/packages.el#L6)
+some packages "have no `:pin` because they're in the same repo".
+
+Doom assumes that if it pins `treemacs`, that pin applies to other packages
+built from the same Git repository (like `treemacs-evil`). That comes somewhat
+naturally to straight.el (since it only checks out each repository once), but it
+does not come naturally to Nix (since it builds each package fully
+independently).
+
+I think I will be able to fix this but I haven't implemented it yet.