diff --git a/outputs.nix b/outputs.nix
index 962a41c..54db6f2 100644
--- a/outputs.nix
+++ b/outputs.nix
@@ -39,7 +39,7 @@
 
   nixosModules = import ./nixos/modules inputs;
 
-  overlays = import ./overlays;
+  overlays = import ./overlays.nix;
 
   hydraJobs = import ./hydra-jobs.nix inputs;
 
diff --git a/overlays.nix b/overlays.nix
new file mode 100644
index 0000000..6d636ec
--- /dev/null
+++ b/overlays.nix
@@ -0,0 +1,41 @@
+{
+  tubslatex = final: prev: {
+    # Based on https://gist.github.com/clefru/9ed1186bf0b76d27e0ad20cbd9966b87
+    tubslatex =
+      prev.lib.overrideDerivation
+        (prev.texlive.combine {
+          inherit (prev.texlive) scheme-full;
+          tubslatex.pkgs = [ (prev.callPackage ../pkgs/tubslatex { }) ];
+        })
+        (oldAttrs: {
+          postBuild =
+            ''
+              # Save the udpmap.cfg because texlive.combine removes it.
+              cat $out/share/texmf/web2c/updmap.cfg > $out/share/texmf/web2c/updmap.cfg.1
+            ''
+            + oldAttrs.postBuild
+            + ''
+              # Move updmap.cfg into its original place and rerun mktexlsr, so that kpsewhich finds it
+              rm $out/share/texmf/web2c/updmap.cfg || true
+              cat $out/share/texmf/web2c/updmap.cfg.1 > $out/share/texmf/web2c/updmap.cfg
+              rm $out/share/texmf/web2c/updmap.cfg.1
+              perl `type -P mktexlsr.pl` $out/share/texmf
+              yes | perl `type -P updmap.pl` --sys --syncwithtrees --force || true
+              perl `type -P updmap.pl` --sys --enable Map=NexusProSerif.map --enable Map=NexusProSans.map
+              # Regenerate .map files.
+              perl `type -P updmap.pl` --sys
+            '';
+        });
+  };
+
+  kanboard = final: prev: {
+    kanboard = prev.kanboard.overrideAttrs (oldAttrs: {
+      src = prev.fetchFromGitHub {
+        owner = "kanboard";
+        repo = "kanboard";
+        rev = "v${oldAttrs.version}";
+        sha256 = "sha256-WG2lTPpRG9KQpRdb+cS7CqF4ZDV7JZ8XtNqAI6eVzm0=";
+      };
+    });
+  };
+}
diff --git a/overlays/default.nix b/overlays/default.nix
deleted file mode 100644
index 8507ceb..0000000
--- a/overlays/default.nix
+++ /dev/null
@@ -1,15 +0,0 @@
-let
-  python3Packages = import ./python3-packages.nix;
-in
-{
-  kanboard = final: prev: {
-    kanboard = prev.kanboard.overrideAttrs (oldAttrs: {
-      src = prev.fetchFromGitHub {
-        owner = "kanboard";
-        repo = "kanboard";
-        rev = "v${oldAttrs.version}";
-        sha256 = "sha256-WG2lTPpRG9KQpRdb+cS7CqF4ZDV7JZ8XtNqAI6eVzm0=";
-      };
-    });
-  };
-}
diff --git a/overlays/python3-packages.nix b/overlays/python3-packages.nix
deleted file mode 100644
index 6eca900..0000000
--- a/overlays/python3-packages.nix
+++ /dev/null
@@ -1,7 +0,0 @@
-self: super: {
-  python3Packages =
-    super.python3Packages
-    // super.recurseIntoAttrs (
-      super.python3Packages.callPackage ../pkgs/python-pkgs { }
-    );
-}
diff --git a/overlays/tubslatex.nix b/overlays/tubslatex.nix
deleted file mode 100644
index da6843d..0000000
--- a/overlays/tubslatex.nix
+++ /dev/null
@@ -1,28 +0,0 @@
-self: super: {
-  # Based on https://gist.github.com/clefru/9ed1186bf0b76d27e0ad20cbd9966b87
-  tubslatex =
-    super.lib.overrideDerivation
-      (super.texlive.combine {
-        inherit (super.texlive) scheme-full;
-        tubslatex.pkgs = [ (super.callPackage ../pkgs/tubslatex { }) ];
-      })
-      (oldAttrs: {
-        postBuild =
-          ''
-            # Save the udpmap.cfg because texlive.combine removes it.
-            cat $out/share/texmf/web2c/updmap.cfg > $out/share/texmf/web2c/updmap.cfg.1
-          ''
-          + oldAttrs.postBuild
-          + ''
-            # Move updmap.cfg into its original place and rerun mktexlsr, so that kpsewhich finds it
-            rm $out/share/texmf/web2c/updmap.cfg || true
-            cat $out/share/texmf/web2c/updmap.cfg.1 > $out/share/texmf/web2c/updmap.cfg
-            rm $out/share/texmf/web2c/updmap.cfg.1
-            perl `type -P mktexlsr.pl` $out/share/texmf
-            yes | perl `type -P updmap.pl` --sys --syncwithtrees --force || true
-            perl `type -P updmap.pl` --sys --enable Map=NexusProSerif.map --enable Map=NexusProSans.map
-            # Regenerate .map files.
-            perl `type -P updmap.pl` --sys
-          '';
-      });
-}
diff --git a/pkgs/python-pkgs/default.nix b/pkgs/python-pkgs/default.nix
deleted file mode 100644
index c1c7b48..0000000
--- a/pkgs/python-pkgs/default.nix
+++ /dev/null
@@ -1 +0,0 @@
-{ callPackage }: { }