diff --git a/doom.nix b/doom.nix
index 255fec5..6231874 100644
--- a/doom.nix
+++ b/doom.nix
@@ -36,6 +36,7 @@
 }:
 let
   inherit (lib) optionalAttrs optionalString;
+  inherit (import ./fetch-overrides.nix) extraPins extraUrls;
 
   # Step 1: determine which Emacs packages to pull in.
   #
@@ -68,29 +69,6 @@ let
 
   doomPackageSet = lib.importJSON "${doomIntermediates}/packages.json";
 
-  # URLs for a few packages used by Doom that have straight recipes but are not
-  # in nixpkgs.
-  extraUrls = {
-    # Straight recipe from el-get
-    font-lock-ext = "https://github.com/sensorflo/font-lock-ext.git";
-    sln-mode = "https://github.com/sensorflo/sln-mode.git";
-    # Straight recipe from emacsmirror-mirror
-    nose = "https://github.com/emacsattic/nose.git";
-    # In nixpkgs, but uses codeberg, for which nixpkgs uses fetchzip.
-    # TODO: consider parsing origEPkg.src.url instead.
-    tree-sitter-indent = "https://codeberg.org/FelipeLema/tree-sitter-indent.el.git";
-    undo-fu = "https://codeberg.org/ideasman42/emacs-undo-fu.git";
-    undo-fu-session = "https://codeberg.org/ideasman42/emacs-undo-fu-session.git";
-    # nixpkgs uses a release from nongnu ELPA.
-    corfu-terminal = "https://codeberg.org/akib/emacs-corfu-terminal";
-  };
-
-  # Pins for packages not pinned by Doom and not in nixpkgs or emacs-overlay.
-  extraPins = {
-    # Looks stable enough we can get away with pinning it.
-    "sly-stepper" = "da84e3bba8466c2290c2dc7c27d7f4c48c27b39e";
-  };
-
   # Step 2: override Emacs packages to respect Doom's pins.
   doomEmacsPackages = (emacsPackagesFor emacs).overrideScope (
     eself: esuper:
diff --git a/fetch-overrides.nix b/fetch-overrides.nix
new file mode 100644
index 0000000..e44e40a
--- /dev/null
+++ b/fetch-overrides.nix
@@ -0,0 +1,23 @@
+# Data loaded by doom.nix.
+{
+  extraUrls = {
+    # Straight recipe from el-get
+    font-lock-ext = "https://github.com/sensorflo/font-lock-ext.git";
+    sln-mode = "https://github.com/sensorflo/sln-mode.git";
+    # Straight recipe from emacsmirror-mirror
+    nose = "https://github.com/emacsattic/nose.git";
+    # In nixpkgs, but uses codeberg, for which nixpkgs uses fetchzip.
+    # TODO: consider parsing origEPkg.src.url instead.
+    tree-sitter-indent = "https://codeberg.org/FelipeLema/tree-sitter-indent.el.git";
+    undo-fu = "https://codeberg.org/ideasman42/emacs-undo-fu.git";
+    undo-fu-session = "https://codeberg.org/ideasman42/emacs-undo-fu-session.git";
+    # nixpkgs uses a release from nongnu ELPA.
+    corfu-terminal = "https://codeberg.org/akib/emacs-corfu-terminal";
+  };
+
+  # Pins for packages not pinned by Doom and not in nixpkgs or emacs-overlay.
+  extraPins = {
+    # Looks stable enough we can get away with pinning it.
+    "sly-stepper" = "da84e3bba8466c2290c2dc7c27d7f4c48c27b39e";
+  };
+}