diff --git a/pkgs/by-name/li/libffi/default.nix b/pkgs/by-name/li/libffi/default.nix
index 455b667..943e3d4 100644
--- a/pkgs/by-name/li/libffi/default.nix
+++ b/pkgs/by-name/li/libffi/default.nix
@@ -2,8 +2,7 @@
 
 # test suite depends on dejagnu which cannot be used during bootstrapping
 # dejagnu also requires tcl which can't be built statically at the moment
-, doCheck ? !(stdenv.hostPlatform.isStatic), dejagnu, nix-update-script, testers
-}:
+, doCheck ? !(stdenv.hostPlatform.isStatic), dejagnu, testers }:
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "libffi";
@@ -47,7 +46,6 @@ stdenv.mkDerivation (finalAttrs: {
   nativeCheckInputs = [ dejagnu ];
 
   passthru = {
-    updateScript = nix-update-script { };
     tests = {
       pkg-config =
         testers.hasPkgConfigModules { package = finalAttrs.finalPackage; };
diff --git a/pkgs/by-name/py/python/default.nix b/pkgs/by-name/py/python/default.nix
index 4ec359a..b79c3b4 100644
--- a/pkgs/by-name/py/python/default.nix
+++ b/pkgs/by-name/py/python/default.nix
@@ -103,6 +103,8 @@ in {
     configd = null;
     sqlite = null;
     tzdata = null;
+    libX11 = null;
+    xorgproto = null;
     libffi = libffiBoot; # without test suite
     stripConfig = true;
     stripIdlelib = true;
diff --git a/pkgs/stdenv/adapters.nix b/pkgs/stdenv/adapters.nix
index 213045c..8770168 100644
--- a/pkgs/stdenv/adapters.nix
+++ b/pkgs/stdenv/adapters.nix
@@ -1,6 +1,6 @@
-/* This file contains various functions that take a stdenv and return
-   a new stdenv with different behaviour, e.g. using a different C
-   compiler.
+/* *
+   Various functions that take a stdenv and return a new stdenv with different behaviour.
+   e.g. using a different C compiler.
 */
 
 { lib, pkgs, config }:
diff --git a/pkgs/stdenv/default.nix b/pkgs/stdenv/default.nix
index 4a1668a..887b566 100644
--- a/pkgs/stdenv/default.nix
+++ b/pkgs/stdenv/default.nix
@@ -7,7 +7,7 @@
 { # Args just for stdenvs' usage
 lib
 # Args to pass on to the pkgset builder, too
-, localSystem, crossSystem, config, overlays, crossOverlays ? [ ] }@args:
+, localSystem, crossSystem, config }@args:
 
 let
   # The native (i.e., impure) build environment.  This one uses the
@@ -34,7 +34,7 @@ let
   stagesCustom = import ./custom args;
 
   # Select the appropriate stages for the platform `system'.
-in if crossSystem != localSystem || crossOverlays != [ ] then
+in if crossSystem != localSystem then
   stagesCross
 else if config ? replaceStdenv then
   stagesCustom
diff --git a/pkgs/stdenv/linux/default.nix b/pkgs/stdenv/linux/default.nix
index 44c954f..1403452 100644
--- a/pkgs/stdenv/linux/default.nix
+++ b/pkgs/stdenv/linux/default.nix
@@ -53,7 +53,7 @@
 # For a TUI (rather than CLI) view, you can use:
 #
 #     $ nix-tree --derivation $(nix-instantiate -A stdenv)
-{ lib, localSystem, crossSystem, config, overlays, crossOverlays ? [ ]
+{ lib, localSystem, crossSystem, config
 
 , bootstrapFiles ? let
   table = {
@@ -224,7 +224,7 @@ let
       };
 
     in {
-      inherit config overlays;
+      inherit config;
       stdenv = thisStdenv;
     };
 
@@ -628,7 +628,7 @@ in assert bootstrapTools.passthru.isFromBootstrapFiles or false; # sanity check
     assert isBuiltByNixpkgsCompiler prevStage.coreutils;
     assert isBuiltByNixpkgsCompiler prevStage.gnugrep;
     assert isBuiltByNixpkgsCompiler prevStage.patchelf; {
-      inherit config overlays;
+      inherit config;
       stdenv = import ../generic lib rec {
         name = "stdenv-linux";
 
@@ -740,6 +740,6 @@ in assert bootstrapTools.passthru.isFromBootstrapFiles or false; # sanity check
     assert isBuiltByNixpkgsCompiler prevStage.coreutils;
     assert isBuiltByNixpkgsCompiler prevStage.gnugrep;
     assert isBuiltByNixpkgsCompiler prevStage.patchelf; {
-      inherit (prevStage) config overlays stdenv;
+      inherit (prevStage) config stdenv;
     })
 ]
diff --git a/pkgs/top-level/base-packages.nix b/pkgs/top-level/base-packages.nix
index addba49..d8fb2e8 100644
--- a/pkgs/top-level/base-packages.nix
+++ b/pkgs/top-level/base-packages.nix
@@ -4,7 +4,7 @@
 # strict sorting has been long lost due to merges. Please use the full-text
 # search of your editor. ;)
 # Hint: ### starts category names.
-{ lib, noSysDirs, config, overlays }:
+{ lib, noSysDirs, config }:
 res: pkgs: super:
 
 with pkgs;
@@ -87,7 +87,7 @@ with pkgs;
   path = ../..;
 
   ### Helper functions.
-  inherit lib config overlays;
+  inherit lib config;
 
   # do not import 'appendToName' to get consistent package-names with the same
   # set of package-parameters: https://github.com/NixOS/nixpkgs/issues/68519
@@ -113,8 +113,6 @@ with pkgs;
     packages, like using pkgs/top-level/release-attrpaths-superset.nix.
   '';
 
-  tests = callPackages ../test { };
-
   # These are used when buiding compiler-rt / libgcc, prior to building libc.
   preLibcCrossHeaders = let inherit (stdenv.targetPlatform) libc;
   in if stdenv.targetPlatform.isMinGW then
diff --git a/pkgs/top-level/default.nix b/pkgs/top-level/default.nix
index d27cb0b..efc076c 100644
--- a/pkgs/top-level/default.nix
+++ b/pkgs/top-level/default.nix
@@ -17,50 +17,29 @@
    or dot-files.
 */
 
-{ # The system packages will be built on. See the manual for the
+{
+# The system packages will be built on. See the manual for the
 # subtle division of labor between these two `*System`s and the three
 # `*Platform`s.
-localSystem
-
-, lib ? import <auxlib>
-
-, # The system packages will ultimately be run on.
-crossSystem ? localSystem
-
-, # Allow a configuration attribute set to be passed in as an argument.
-config ? { }
-
-, # List of overlays layers used to extend Nixpkgs.
-overlays ? [ ]
-
-, # List of overlays to apply to target packages only.
-crossOverlays ? [ ]
-
-, # A function booting the final package set for a specific standard
-# environment. See below for the arguments given to that function, the type of
-# list it returns.
-stdenvStages ? import ../stdenv
+localSystem, lib ? import <auxlib>
+  # The system packages will ultimately be run on.
+, crossSystem ? localSystem
+  # Allow a configuration attribute set to be passed in as an argument.
+, config ? { }
+  # A function booting the final package set for a specific standard
+  # environment. See below for the arguments given to that function, the type of
+  # list it returns.
+, stdenvStages ? import ../stdenv
 
 , # Ignore unexpected args.
 ... }@args:
-
-let # Rename the function arguments
+let
+  # Rename the function arguments
   config0 = config;
   crossSystem0 = crossSystem;
-
 in let
   inherit (lib) throwIfNot;
 
-  checked = throwIfNot (lib.isList overlays)
-    "The overlays argument to nixpkgs must be a list." lib.foldr (x:
-      throwIfNot (lib.isFunction x)
-      "All overlays passed to nixpkgs must be functions.") (r: r) overlays
-    throwIfNot (lib.isList crossOverlays)
-    "The crossOverlays argument to nixpkgs must be a list." lib.foldr (x:
-      throwIfNot (lib.isFunction x)
-      "All crossOverlays passed to nixpkgs must be functions.") (r: r)
-    crossOverlays;
-
   localSystem = lib.systems.elaborate args.localSystem;
 
   # Condition preserves sharing which in turn affects equality.
@@ -135,10 +114,8 @@ in let
 
   boot = import ../stdenv/booter.nix { inherit lib allPackages; };
 
-  stages = stdenvStages {
-    inherit lib localSystem crossSystem config overlays crossOverlays;
-  };
+  stages = stdenvStages { inherit lib localSystem crossSystem config; };
 
   pkgs = boot stages;
 
-in checked pkgs
+in pkgs
diff --git a/pkgs/top-level/splice.nix b/pkgs/top-level/splice.nix
index cf4bfa3..200a11c 100644
--- a/pkgs/top-level/splice.nix
+++ b/pkgs/top-level/splice.nix
@@ -105,14 +105,6 @@ let
     inherit (pkgs.stdenv) buildPlatform targetPlatform hostPlatform;
   };
 
-  splicedPackagesWithXorg = splicedPackages
-    // builtins.removeAttrs splicedPackages.xorg [
-      "callPackage"
-      "newScope"
-      "overrideScope"
-      "packages"
-    ];
-
 in {
   inherit splicePackages;
 
@@ -121,9 +113,9 @@ in {
   # `newScope' for sets of packages in `pkgs' (see e.g. `gnome' below).
   callPackage = pkgs.newScope { };
 
-  callPackages = lib.callPackagesWith splicedPackagesWithXorg;
+  callPackages = lib.callPackagesWith splicedPackages;
 
-  newScope = extra: lib.callPackageWith (splicedPackagesWithXorg // extra);
+  newScope = extra: lib.callPackageWith (splicedPackages // extra);
 
   # prefill 2 fields of the function for convenience
   makeScopeWithSplicing =
diff --git a/pkgs/top-level/stage.nix b/pkgs/top-level/stage.nix
index f361ecc..9184483 100644
--- a/pkgs/top-level/stage.nix
+++ b/pkgs/top-level/stage.nix
@@ -14,22 +14,13 @@ let
   # By defining it at the top of the file,
   # this value gets reused even if this file is imported multiple times,
   # thanks to Nix's import-value cache.
-  # autoCalledPackages = import ./by-name-overlay.nix ../by-name;
+  autoCalledPackages = import ./by-name-overlay.nix ../by-name;
 
 in {
-## Misc parameters kept the same for all stages
-##
+# Misc parameters kept the same for all stages
+lib, nixpkgsFun
 
-# Utility functions, could just import but passing in for efficiency
-lib
-
-, # Use to reevaluate Nixpkgs
-nixpkgsFun
-
-## Other parameters
-##
-
-, # Either null or an object in the form:
+# Either null or an object in the form:
 #
 #   {
 #     pkgsBuildBuild = ...;
@@ -45,75 +36,30 @@ nixpkgsFun
 # they are instead defined internally as the current stage. This allows us to
 # avoid expensive splicing. `pkgsHostTarget` is skipped because it is always
 # defined as the current stage.
-adjacentPackages
+, adjacentPackages
 
-, # The standard environment to use for building packages.
-stdenv
+# The standard environment to use for building packages.
+, stdenv
 
-, # This is used because stdenv replacement and the stdenvCross do benefit from
+# This is used because stdenv replacement and the stdenvCross do benefit from
 # the overridden configuration provided by the user, as opposed to the normal
 # bootstrapping stdenvs.
-allowCustomOverrides
+, allowCustomOverrides
 
-, # Non-GNU/Linux OSes are currently "impure" platforms, with their libc
+# Non-GNU/Linux OSes are currently "impure" platforms, with their libc
 # outside of the store.  Thus, GCC, GFortran, & co. must always look for files
 # in standard system directories (/usr/include, etc.)
-noSysDirs ? stdenv.buildPlatform.system != "x86_64-freebsd"
+, noSysDirs ? stdenv.buildPlatform.system != "x86_64-freebsd"
   && stdenv.buildPlatform.system != "i686-freebsd"
   && stdenv.buildPlatform.system != "x86_64-solaris"
   && stdenv.buildPlatform.system != "x86_64-kfreebsd-gnu"
 
-, # The configuration attribute set
-config
-
-, # A list of overlays (Additional `self: super: { .. }` customization
-# functions) to be fixed together in the produced package set
-overlays
+  # The configuration attribute set
+, config
 
 }@args:
 
 let
-  # This is a function from parsed platforms (like
-  # stdenv.hostPlatform.parsed) to parsed platforms.
-  makeMuslParsedPlatform = parsed:
-    # The following line guarantees that the output of this function
-    # is a well-formed platform with no missing fields.  It will be
-    # uncommented in a separate PR, in case it breaks the build.
-    #(x: lib.trivial.pipe x [ (x: builtins.removeAttrs x [ "_type" ]) lib.systems.parse.mkSystem ])
-    (parsed // {
-      abi = {
-        gnu = lib.systems.parse.abis.musl;
-        gnueabi = lib.systems.parse.abis.musleabi;
-        gnueabihf = lib.systems.parse.abis.musleabihf;
-        gnuabin32 = lib.systems.parse.abis.muslabin32;
-        gnuabi64 = lib.systems.parse.abis.muslabi64;
-        gnuabielfv2 = lib.systems.parse.abis.musl;
-        gnuabielfv1 = lib.systems.parse.abis.musl;
-        # The following two entries ensure that this function is idempotent.
-        musleabi = lib.systems.parse.abis.musleabi;
-        musleabihf = lib.systems.parse.abis.musleabihf;
-        muslabin32 = lib.systems.parse.abis.muslabin32;
-        muslabi64 = lib.systems.parse.abis.muslabi64;
-      }.${parsed.abi.name} or lib.systems.parse.abis.musl;
-    });
-
-  stdenvAdapters = self: super:
-    let
-      res = import ../stdenv/adapters.nix {
-        inherit lib config;
-        pkgs = self;
-      };
-    in res // { stdenvAdapters = res; };
-
-  trivialBuilders = self: super:
-    import ../build-support/trivial-builders {
-      inherit lib;
-      inherit (self) config;
-      inherit (self) runtimeShell stdenv stdenvNoCC;
-      inherit (self.pkgsBuildHost) jq shellcheck-minimal;
-      inherit (self.pkgsBuildHost.xorg) lndir;
-    };
-
   stdenvBootstappingAndPlatforms = self: super:
     let
       withFallback = thisPkgs:
@@ -148,31 +94,25 @@ let
       inherit stdenv;
     };
 
+  stdenvAdapters = self: super:
+    let
+      res = import ../stdenv/adapters.nix {
+        inherit lib config;
+        pkgs = self;
+      };
+    in res // { stdenvAdapters = res; };
+
+  trivialBuilders = self: super:
+    import ../build-support/trivial-builders {
+      inherit lib;
+      inherit (self) config;
+      inherit (self) runtimeShell stdenv stdenvNoCC;
+      inherit (self.pkgsBuildHost) jq shellcheck-minimal;
+      inherit (self.pkgsBuildHost.xorg) lndir;
+    };
+
   splice = self: super: import ./splice.nix lib self (adjacentPackages != null);
 
-  basePackages = self: super:
-    let
-      res =
-        import ./base-packages.nix { inherit lib noSysDirs config overlays; }
-        res self super;
-    in res;
-
-  commonUpdaterPackages = self: super:
-    let
-      res = import ../common-updater/packages.nix {
-        inherit lib noSysDirs config overlays;
-      } res self super;
-    in res;
-
-  buildSupportPackages = self: super:
-    let
-      res = import ../build-support/packages.nix {
-        inherit lib noSysDirs config overlays;
-      } res self super;
-    in res;
-
-  # aliases = self: super: lib.optionalAttrs config.allowAliases (import ./aliases.nix lib self super);
-
   byNamePackages = self: super:
     let
       inherit (builtins) readDir;
@@ -208,27 +148,47 @@ let
         _internalCallByNamePackageFile = file: self.callPackage file { };
       } // (mapAttrs (name: self._internalCallByNamePackageFile) packageFiles)
         // lib.foldl (acc: path:
-          (import "${path}/packages.nix" {
-            inherit lib noSysDirs config overlays;
-          } res self super) // acc) { } packageGroupFiles;
+          (import "${path}/packages.nix" { inherit lib noSysDirs config; } res
+            self super) // acc) { } packageGroupFiles;
     in res;
 
-  # stdenvOverrides is used to avoid having multiple of versions
-  # of certain dependencies that were used in bootstrapping the
-  # standard environment.
-  stdenvOverrides = self: super:
-    (super.stdenv.overrides or (_: _: { })) self super;
+  basePackages = self: super:
+    let
+      res =
+        import ./base-packages.nix { inherit lib noSysDirs config; } res self
+        super;
+    in res;
 
-  # Allow packages to be overridden globally via the `packageOverrides'
-  # configuration option, which must be a function that takes `pkgs'
-  # as an argument and returns a set of new or overridden packages.
-  # The `packageOverrides' function is called with the *original*
-  # (un-overridden) set of packages, allowing packageOverrides
-  # attributes to refer to the original attributes (e.g. "foo =
-  # ... pkgs.foo ...").
-  configOverrides = self: super:
-    lib.optionalAttrs allowCustomOverrides
-    ((config.packageOverrides or (super: { })) super);
+  buildSupportPackages = self: super:
+    let
+      res =
+        import ../build-support/packages.nix { inherit lib noSysDirs config; }
+        res self super;
+    in res;
+
+  # This is a function from parsed platforms (like
+  # stdenv.hostPlatform.parsed) to parsed platforms.
+  makeMuslParsedPlatform = parsed:
+    # The following line guarantees that the output of this function
+    # is a well-formed platform with no missing fields.  It will be
+    # uncommented in a separate PR, in case it breaks the build.
+    #(x: lib.trivial.pipe x [ (x: builtins.removeAttrs x [ "_type" ]) lib.systems.parse.mkSystem ])
+    (parsed // {
+      abi = {
+        gnu = lib.systems.parse.abis.musl;
+        gnueabi = lib.systems.parse.abis.musleabi;
+        gnueabihf = lib.systems.parse.abis.musleabihf;
+        gnuabin32 = lib.systems.parse.abis.muslabin32;
+        gnuabi64 = lib.systems.parse.abis.muslabi64;
+        gnuabielfv2 = lib.systems.parse.abis.musl;
+        gnuabielfv1 = lib.systems.parse.abis.musl;
+        # The following two entries ensure that this function is idempotent.
+        musleabi = lib.systems.parse.abis.musleabi;
+        musleabihf = lib.systems.parse.abis.musleabihf;
+        muslabin32 = lib.systems.parse.abis.muslabin32;
+        muslabi64 = lib.systems.parse.abis.muslabi64;
+      }.${parsed.abi.name} or lib.systems.parse.abis.musl;
+    });
 
   # Convenience attributes for instantitating package sets. Each of
   # these will instantiate a new version of allPackages. Currently the
@@ -248,7 +208,6 @@ let
       lib.systems.examples;
 
     pkgsLLVM = nixpkgsFun {
-      overlays = [ (self': super': { pkgsLLVM = super'; }) ] ++ overlays;
       # Bootstrap a cross stdenv using the LLVM toolchain.
       # This is currently not possible when compiling natively,
       # so we don't need to check hostPlatform != buildPlatform.
@@ -264,7 +223,6 @@ let
     pkgsMusl =
       if stdenv.hostPlatform.isLinux && stdenv.buildPlatform.is64bit then
         nixpkgsFun {
-          overlays = [ (self': super': { pkgsMusl = super'; }) ] ++ overlays;
           ${
             if stdenv.hostPlatform == stdenv.buildPlatform then
               "localSystem"
@@ -282,8 +240,6 @@ let
     pkgsi686Linux =
       if stdenv.hostPlatform.isLinux && stdenv.hostPlatform.isx86 then
         nixpkgsFun {
-          overlays = [ (self': super': { pkgsi686Linux = super'; }) ]
-            ++ overlays;
           ${
             if stdenv.hostPlatform == stdenv.buildPlatform then
               "localSystem"
@@ -301,8 +257,6 @@ let
     # x86_64-darwin packages for aarch64-darwin users to use with Rosetta for incompatible packages
     pkgsx86_64Darwin = if stdenv.hostPlatform.isDarwin then
       nixpkgsFun {
-        overlays = [ (self': super': { pkgsx86_64Darwin = super'; }) ]
-          ++ overlays;
         localSystem = {
           parsed = stdenv.hostPlatform.parsed // {
             cpu = lib.systems.parse.cpuTypes.x86_64;
@@ -323,28 +277,9 @@ let
           lib.systems.elaborate "${stdenv.hostPlatform.parsed.cpu.name}-linux";
       };
 
-    # Extend the package set with zero or more overlays. This preserves
-    # preexisting overlays. Prefer to initialize with the right overlays
-    # in one go when calling Nixpkgs, for performance and simplicity.
-    appendOverlays = extraOverlays:
-      if extraOverlays == [ ] then
-        self
-      else
-        nixpkgsFun { overlays = args.overlays ++ extraOverlays; };
-
-    # NOTE: each call to extend causes a full nixpkgs rebuild, adding ~130MB
-    #       of allocations. DO NOT USE THIS IN NIXPKGS.
-    #
-    # Extend the package set with a single overlay. This preserves
-    # preexisting overlays. Prefer to initialize with the right overlays
-    # in one go when calling Nixpkgs, for performance and simplicity.
-    # Prefer appendOverlays if used repeatedly.
-    extend = f: self.appendOverlays [ f ];
-
     # Fully static packages.
     # Currently uses Musl on Linux (couldn’t get static glibc to work).
     pkgsStatic = nixpkgsFun ({
-      overlays = [ (self': super': { pkgsStatic = super'; }) ] ++ overlays;
       crossSystem = {
         isStatic = true;
         parsed = if stdenv.isLinux then
@@ -355,22 +290,15 @@ let
         gcc.abi = "elfv2";
       };
     });
-
-    pkgsExtraHardening = nixpkgsFun {
-      overlays = [
-        (self': super': {
-          pkgsExtraHardening = super';
-          stdenv = super'.withDefaultHardeningFlags
-            (super'.stdenv.cc.defaultHardeningFlags
-              ++ [ "zerocallusedregs" "trivialautovarinit" ]) super'.stdenv;
-        })
-      ] ++ overlays;
-    };
   };
 
+  # stdenvOverrides is used to avoid having multiple of versions
+  # of certain dependencies that were used in bootstrapping the
+  # standard environment.
+  stdenvOverrides = self: super:
+    (super.stdenv.overrides or (_: _: { })) self super;
+
   # The complete chain of package set builders, applied from top to bottom.
-  # stdenvOverlays must be last as it brings package forward from the
-  # previous bootstrapping phases which have already been overlayed.
   toFix = lib.foldl' (lib.flip lib.extends) (self: { }) ([
     stdenvBootstappingAndPlatforms
     stdenvAdapters
@@ -378,12 +306,10 @@ let
     splice
     byNamePackages
     basePackages
-    commonUpdaterPackages
     buildSupportPackages
     otherPackageSets
-    # aliases
-    configOverrides
-  ] ++ overlays ++ [ stdenvOverrides ]);
+    stdenvOverrides
+  ]);
 
   # Return the complete set of packages.
 in lib.fix toFix