diff --git a/doc/manual/source/release-notes/rl-2.28.md b/doc/manual/source/release-notes/rl-2.28.md
index 6da09546e..b2fd26054 100644
--- a/doc/manual/source/release-notes/rl-2.28.md
+++ b/doc/manual/source/release-notes/rl-2.28.md
@@ -46,7 +46,7 @@ This completes the infrastructure overhaul for the [RFC 132](https://github.com/
   @@ @@
   -#include "config.hh"
   +// Additionally renamed to distinguish from components' config headers.
-  +#include "nix/util/configuration.hh"
+  +#include "nix/main/configuration.hh"
   @@ @@
   -#if HAVE_ACL_SUPPORT
   +#if NIX_SUPPORT_ACL
diff --git a/maintainers/flake-module.nix b/maintainers/flake-module.nix
index 224f47268..052d66010 100644
--- a/maintainers/flake-module.nix
+++ b/maintainers/flake-module.nix
@@ -180,8 +180,14 @@
               ''^src/libflake/lockfile\.cc$''
               ''^src/libflake/include/nix/flake/lockfile\.hh$''
               ''^src/libflake/url-name\.cc$''
+              ''^src/libmain/args/root\.hh$''
+              ''^src/libmain/args\.cc$''
+              ''^src/libmain/args\.hh$''
               ''^src/libmain/common-args\.cc$''
               ''^src/libmain/include/nix/main/common-args\.hh$''
+              ''^src/libmain/include/nix/main/config-impl\.hh$''
+              ''^src/libmain/config\.cc$''
+              ''^src/libmain/include/nix/main/config\.hh$''
               ''^src/libmain/loggers\.cc$''
               ''^src/libmain/include/nix/main/loggers\.hh$''
               ''^src/libmain/progress-bar\.cc$''
@@ -314,9 +320,6 @@
               ''^src/libutil-c/nix_api_util_internal\.h$''
               ''^src/libutil/archive\.cc$''
               ''^src/libutil/include/nix/util/archive\.hh$''
-              ''^src/libutil/args\.cc$''
-              ''^src/libutil/include/nix/util/args\.hh$''
-              ''^src/libutil/include/nix/util/args/root\.hh$''
               ''^src/libutil/include/nix/util/callback\.hh$''
               ''^src/libutil/canon-path\.cc$''
               ''^src/libutil/include/nix/util/canon-path\.hh$''
@@ -324,9 +327,6 @@
               ''^src/libutil/include/nix/util/closure\.hh$''
               ''^src/libutil/include/nix/util/comparator\.hh$''
               ''^src/libutil/compute-levels\.cc$''
-              ''^src/libutil/include/nix/util/config-impl\.hh$''
-              ''^src/libutil/configuration\.cc$''
-              ''^src/libutil/include/nix/util/configuration\.hh$''
               ''^src/libutil/current-process\.cc$''
               ''^src/libutil/include/nix/util/current-process\.hh$''
               ''^src/libutil/english\.cc$''
diff --git a/src/libcmd/common-eval-args.cc b/src/libcmd/common-eval-args.cc
index d275beb12..14d2acf4a 100644
--- a/src/libcmd/common-eval-args.cc
+++ b/src/libcmd/common-eval-args.cc
@@ -2,7 +2,7 @@
 #include "nix/expr/eval-settings.hh"
 #include "nix/cmd/common-eval-args.hh"
 #include "nix/main/shared.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/filetransfer.hh"
 #include "nix/expr/eval.hh"
 #include "nix/fetchers/fetchers.hh"
diff --git a/src/libcmd/include/nix/cmd/command.hh b/src/libcmd/include/nix/cmd/command.hh
index 20cd1abc1..148a36a96 100644
--- a/src/libcmd/include/nix/cmd/command.hh
+++ b/src/libcmd/include/nix/cmd/command.hh
@@ -2,7 +2,7 @@
 ///@file
 
 #include "nix/cmd/installable-value.hh"
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/cmd/common-eval-args.hh"
 #include "nix/store/path.hh"
 #include "nix/flake/lockfile.hh"
diff --git a/src/libcmd/include/nix/cmd/common-eval-args.hh b/src/libcmd/include/nix/cmd/common-eval-args.hh
index 6f3367e58..f137d8a67 100644
--- a/src/libcmd/include/nix/cmd/common-eval-args.hh
+++ b/src/libcmd/include/nix/cmd/common-eval-args.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/util/canon-path.hh"
 #include "nix/main/common-args.hh"
 #include "nix/expr/search-path.hh"
diff --git a/src/libcmd/include/nix/cmd/compatibility-settings.hh b/src/libcmd/include/nix/cmd/compatibility-settings.hh
index c7061a0a1..bfc699e8a 100644
--- a/src/libcmd/include/nix/cmd/compatibility-settings.hh
+++ b/src/libcmd/include/nix/cmd/compatibility-settings.hh
@@ -1,5 +1,5 @@
 #pragma once
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 
 namespace nix {
 struct CompatibilitySettings : public Config
diff --git a/src/libcmd/include/nix/cmd/misc-store-flags.hh b/src/libcmd/include/nix/cmd/misc-store-flags.hh
index c9467ad8e..863d9973d 100644
--- a/src/libcmd/include/nix/cmd/misc-store-flags.hh
+++ b/src/libcmd/include/nix/cmd/misc-store-flags.hh
@@ -1,4 +1,4 @@
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/store/content-address.hh"
 
 namespace nix::flag {
diff --git a/src/libexpr-c/nix_api_external.cc b/src/libexpr-c/nix_api_external.cc
index 04d2e52b5..2d1f743b4 100644
--- a/src/libexpr-c/nix_api_external.cc
+++ b/src/libexpr-c/nix_api_external.cc
@@ -1,5 +1,5 @@
 #include "nix/expr/attr-set.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/expr/eval.hh"
 #include "nix/store/globals.hh"
 #include "nix/expr/value.hh"
diff --git a/src/libexpr-c/nix_api_value.cc b/src/libexpr-c/nix_api_value.cc
index 298d94845..3f8bc36b5 100644
--- a/src/libexpr-c/nix_api_value.cc
+++ b/src/libexpr-c/nix_api_value.cc
@@ -1,5 +1,5 @@
 #include "nix/expr/attr-set.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/expr/eval.hh"
 #include "nix/store/globals.hh"
 #include "nix/store/path.hh"
diff --git a/src/libexpr/eval-gc.cc b/src/libexpr/eval-gc.cc
index bec668001..21426a40f 100644
--- a/src/libexpr/eval-gc.cc
+++ b/src/libexpr/eval-gc.cc
@@ -1,7 +1,7 @@
 #include "nix/util/error.hh"
 #include "nix/util/environment-variables.hh"
 #include "nix/expr/eval-settings.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/util/serialise.hh"
 #include "nix/expr/eval-gc.hh"
 
diff --git a/src/libexpr/include/nix/expr/eval-settings.hh b/src/libexpr/include/nix/expr/eval-settings.hh
index 8d3db59b3..b1f79f32a 100644
--- a/src/libexpr/include/nix/expr/eval-settings.hh
+++ b/src/libexpr/include/nix/expr/eval-settings.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/source-path.hh"
 
 namespace nix {
diff --git a/src/libexpr/include/nix/expr/eval.hh b/src/libexpr/include/nix/expr/eval.hh
index ffbc84bcd..da8921f2a 100644
--- a/src/libexpr/include/nix/expr/eval.hh
+++ b/src/libexpr/include/nix/expr/eval.hh
@@ -8,7 +8,7 @@
 #include "nix/expr/value.hh"
 #include "nix/expr/nixexpr.hh"
 #include "nix/expr/symbol-table.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/experimental-features.hh"
 #include "nix/util/position.hh"
 #include "nix/util/pos-table.hh"
diff --git a/src/libfetchers/include/nix/fetchers/fetch-settings.hh b/src/libfetchers/include/nix/fetchers/fetch-settings.hh
index 7bd04db53..955939626 100644
--- a/src/libfetchers/include/nix/fetchers/fetch-settings.hh
+++ b/src/libfetchers/include/nix/fetchers/fetch-settings.hh
@@ -2,7 +2,7 @@
 ///@file
 
 #include "nix/util/types.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/ref.hh"
 #include "nix/util/sync.hh"
 
diff --git a/src/libflake/config.cc b/src/libflake/config.cc
index 030104e7f..74598865c 100644
--- a/src/libflake/config.cc
+++ b/src/libflake/config.cc
@@ -1,5 +1,5 @@
 #include "nix/util/users.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/flake/settings.hh"
 #include "nix/flake/flake.hh"
 
diff --git a/src/libflake/include/nix/flake/settings.hh b/src/libflake/include/nix/flake/settings.hh
index b3bffad4c..61d8abcba 100644
--- a/src/libflake/include/nix/flake/settings.hh
+++ b/src/libflake/include/nix/flake/settings.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 
 #include <sys/types.h>
 
diff --git a/src/libutil/args.cc b/src/libmain/args.cc
similarity index 99%
rename from src/libutil/args.cc
rename to src/libmain/args.cc
index d8d004e6f..237717ef6 100644
--- a/src/libutil/args.cc
+++ b/src/libmain/args.cc
@@ -1,5 +1,5 @@
-#include "nix/util/args.hh"
-#include "nix/util/args/root.hh"
+#include "nix/main/args.hh"
+#include "nix/main/args/root.hh"
 #include "nix/util/hash.hh"
 #include "nix/util/environment-variables.hh"
 #include "nix/util/signals.hh"
diff --git a/src/libmain/common-args.cc b/src/libmain/common-args.cc
index dcf252a4f..6a1ba2d61 100644
--- a/src/libmain/common-args.cc
+++ b/src/libmain/common-args.cc
@@ -1,8 +1,8 @@
 #include <nlohmann/json.hpp>
 
 #include "nix/main/common-args.hh"
-#include "nix/util/args/root.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/args/root.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/globals.hh"
 #include "nix/util/logging.hh"
 #include "nix/main/loggers.hh"
diff --git a/src/libutil/config-global.cc b/src/libmain/config-global.cc
similarity index 97%
rename from src/libutil/config-global.cc
rename to src/libmain/config-global.cc
index 94d715443..7bce2b65c 100644
--- a/src/libutil/config-global.cc
+++ b/src/libmain/config-global.cc
@@ -1,4 +1,4 @@
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 
 #include <nlohmann/json.hpp>
 
diff --git a/src/libmain/config-upstream.cc b/src/libmain/config-upstream.cc
new file mode 100644
index 000000000..60dce874c
--- /dev/null
+++ b/src/libmain/config-upstream.cc
@@ -0,0 +1,44 @@
+namespace nix {
+
+#include "nix/util/fs-sink.hh"
+#include "nix/util/logging.hh"
+
+struct LoggerSettings : Config
+{
+    Setting<bool> showTrace{
+        this,
+        false,
+        "show-trace",
+        R"(
+          Whether Nix should print out a stack trace in case of Nix
+          expression evaluation errors.
+        )"};
+};
+
+static GlobalConfig::Register r1(&restoreSinkSettings);
+
+struct RestoreSinkSettings : Config
+{
+    Setting<bool> preallocateContents{
+        this, false, "preallocate-contents", "Whether to preallocate files when writing objects with known size."};
+};
+
+static GlobalConfig::Register rLoggerSettings(&loggerSettings);
+
+struct ArchiveSettings : Config
+{
+    Setting<bool> useCaseHack
+    {
+        this,
+#if __APPLE__
+            true,
+#else
+            false,
+#endif
+            "use-case-hack", "Whether to enable a macOS-specific hack for dealing with file name case collisions."
+    };
+};
+
+static GlobalConfig::Register rArchiveSettings(&archiveSettings);
+
+}
diff --git a/src/libutil/configuration.cc b/src/libmain/configuration.cc
similarity index 94%
rename from src/libutil/configuration.cc
rename to src/libmain/configuration.cc
index 314ae34db..4c7d1180c 100644
--- a/src/libutil/configuration.cc
+++ b/src/libmain/configuration.cc
@@ -1,12 +1,12 @@
-#include "nix/util/configuration.hh"
-#include "nix/util/args.hh"
-#include "nix/util/abstract-setting-to-json.hh"
+#include "nix/main/configuration.hh"
+#include "nix/main/args.hh"
+#include "nix/main/abstract-setting-to-json.hh"
 #include "nix/util/environment-variables.hh"
 #include "nix/util/experimental-features.hh"
 #include "nix/util/util.hh"
 #include "nix/util/file-system.hh"
 
-#include "nix/util/config-impl.hh"
+#include "nix/main/config-impl.hh"
 
 #include <nlohmann/json.hpp>
 
@@ -464,26 +464,4 @@ void OptionalPathSetting::operator =(const std::optional<Path> & v)
     this->assign(v);
 }
 
-bool ExperimentalFeatureSettings::isEnabled(const ExperimentalFeature & feature) const
-{
-    auto & f = experimentalFeatures.get();
-    return std::find(f.begin(), f.end(), feature) != f.end();
-}
-
-void ExperimentalFeatureSettings::require(const ExperimentalFeature & feature) const
-{
-    if (!isEnabled(feature))
-        throw MissingExperimentalFeature(feature);
-}
-
-bool ExperimentalFeatureSettings::isEnabled(const std::optional<ExperimentalFeature> & feature) const
-{
-    return !feature || isEnabled(*feature);
-}
-
-void ExperimentalFeatureSettings::require(const std::optional<ExperimentalFeature> & feature) const
-{
-    if (feature) require(*feature);
-}
-
 }
diff --git a/src/libutil/include/nix/util/abstract-setting-to-json.hh b/src/libmain/include/nix/main/abstract-setting-to-json.hh
similarity index 91%
rename from src/libutil/include/nix/util/abstract-setting-to-json.hh
rename to src/libmain/include/nix/main/abstract-setting-to-json.hh
index 2848f8afe..3252fb1f7 100644
--- a/src/libutil/include/nix/util/abstract-setting-to-json.hh
+++ b/src/libmain/include/nix/main/abstract-setting-to-json.hh
@@ -2,7 +2,7 @@
 ///@file
 
 #include <nlohmann/json.hpp>
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/json-utils.hh"
 
 namespace nix {
diff --git a/src/libutil/include/nix/util/args.hh b/src/libmain/include/nix/main/args.hh
similarity index 100%
rename from src/libutil/include/nix/util/args.hh
rename to src/libmain/include/nix/main/args.hh
diff --git a/src/libutil/include/nix/util/args/root.hh b/src/libmain/include/nix/main/args/root.hh
similarity index 98%
rename from src/libutil/include/nix/util/args/root.hh
rename to src/libmain/include/nix/main/args/root.hh
index cdc9be613..ec58f6bf0 100644
--- a/src/libutil/include/nix/util/args/root.hh
+++ b/src/libmain/include/nix/main/args/root.hh
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 
 namespace nix {
 
diff --git a/src/libmain/include/nix/main/common-args.hh b/src/libmain/include/nix/main/common-args.hh
index cc6d3d3f0..1ed78dd46 100644
--- a/src/libmain/include/nix/main/common-args.hh
+++ b/src/libmain/include/nix/main/common-args.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/util/repair-flag.hh"
 
 namespace nix {
diff --git a/src/libutil/include/nix/util/config-global.hh b/src/libmain/include/nix/main/config-global.hh
similarity index 95%
rename from src/libutil/include/nix/util/config-global.hh
rename to src/libmain/include/nix/main/config-global.hh
index 44f89e06d..874141624 100644
--- a/src/libutil/include/nix/util/config-global.hh
+++ b/src/libmain/include/nix/main/config-global.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 
 namespace nix {
 
diff --git a/src/libutil/include/nix/util/config-impl.hh b/src/libmain/include/nix/main/config-impl.hh
similarity index 98%
rename from src/libutil/include/nix/util/config-impl.hh
rename to src/libmain/include/nix/main/config-impl.hh
index 15e0c9554..203a69866 100644
--- a/src/libutil/include/nix/util/config-impl.hh
+++ b/src/libmain/include/nix/main/config-impl.hh
@@ -12,8 +12,8 @@
  * instantiation.
  */
 
-#include "nix/util/configuration.hh"
-#include "nix/util/args.hh"
+#include "nix/main/configuration.hh"
+#include "nix/main/args.hh"
 
 namespace nix {
 
diff --git a/src/libutil/include/nix/util/configuration.hh b/src/libmain/include/nix/main/configuration.hh
similarity index 98%
rename from src/libutil/include/nix/util/configuration.hh
rename to src/libmain/include/nix/main/configuration.hh
index dc939dfce..e70c2f29f 100644
--- a/src/libutil/include/nix/util/configuration.hh
+++ b/src/libmain/include/nix/main/configuration.hh
@@ -258,10 +258,6 @@ public:
         , documentDefault(documentDefault)
     { }
 
-    operator const T &() const { return value; }
-    operator T &() { return value; }
-    const T & get() const { return value; }
-    T & get() { return value; }
     template<typename U>
     bool operator ==(const U & v2) const { return value == v2; }
     template<typename U>
diff --git a/src/libmain/include/nix/main/meson.build b/src/libmain/include/nix/main/meson.build
index 992a5ff0e..0231fa279 100644
--- a/src/libmain/include/nix/main/meson.build
+++ b/src/libmain/include/nix/main/meson.build
@@ -3,7 +3,13 @@
 include_dirs = [include_directories('../..')]
 
 headers = files(
+  'abstract-setting-to-json.hh',
+  'args.hh',
+  'args/root.hh',
   'common-args.hh',
+  'config-impl.hh',
+  'config-global.hh',
+  'configuration.hh',
   'loggers.hh',
   'plugin.hh',
   'progress-bar.hh',
diff --git a/src/libmain/include/nix/main/shared.hh b/src/libmain/include/nix/main/shared.hh
index 2ff57135b..aaef4c673 100644
--- a/src/libmain/include/nix/main/shared.hh
+++ b/src/libmain/include/nix/main/shared.hh
@@ -3,8 +3,8 @@
 
 #include "nix/util/file-descriptor.hh"
 #include "nix/util/processes.hh"
-#include "nix/util/args.hh"
-#include "nix/util/args/root.hh"
+#include "nix/main/args.hh"
+#include "nix/main/args/root.hh"
 #include "nix/main/common-args.hh"
 #include "nix/store/path.hh"
 #include "nix/store/derived-path.hh"
diff --git a/src/libmain/meson.build b/src/libmain/meson.build
index 65fcb6239..90c1fb0a8 100644
--- a/src/libmain/meson.build
+++ b/src/libmain/meson.build
@@ -54,7 +54,9 @@ config_priv_h = configure_file(
 subdir('nix-meson-build-support/common')
 
 sources = files(
+  'args.cc',
   'common-args.cc',
+  'configuration.cc',
   'loggers.cc',
   'plugin.cc',
   'progress-bar.cc',
diff --git a/src/libmain/plugin.cc b/src/libmain/plugin.cc
index db686a251..38f4614c2 100644
--- a/src/libmain/plugin.cc
+++ b/src/libmain/plugin.cc
@@ -4,7 +4,7 @@
 
 #include <filesystem>
 
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/util/signals.hh"
 #include "nix/util/file-system.hh"
 
diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc
index 5c8b75cb9..030c0ee9a 100644
--- a/src/libstore/build/derivation-goal.cc
+++ b/src/libstore/build/derivation-goal.cc
@@ -5,7 +5,7 @@
 #  include "nix/store/build/derivation-builder.hh"
 #endif
 #include "nix/util/processes.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/build/worker.hh"
 #include "nix/util/util.hh"
 #include "nix/util/compression.hh"
diff --git a/src/libstore/content-address.cc b/src/libstore/content-address.cc
index 5d27c4136..217969d88 100644
--- a/src/libstore/content-address.cc
+++ b/src/libstore/content-address.cc
@@ -1,6 +1,6 @@
-#include "nix/util/args.hh"
 #include "nix/store/content-address.hh"
 #include "nix/util/split.hh"
+#include "nix/util/experimental-feature-settings.hh"
 
 namespace nix {
 
diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index 8f7514273..9df8ecb0b 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -13,7 +13,7 @@
 #include "nix/util/finally.hh"
 #include "nix/util/archive.hh"
 #include "nix/store/derivations.hh"
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/util/git.hh"
 
 #ifndef _WIN32 // TODO need graceful async exit support on Windows?
diff --git a/src/libstore/filetransfer.cc b/src/libstore/filetransfer.cc
index 1d2280a2d..e6524bea6 100644
--- a/src/libstore/filetransfer.cc
+++ b/src/libstore/filetransfer.cc
@@ -1,6 +1,6 @@
 #include "nix/store/filetransfer.hh"
 #include "nix/store/globals.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/store-api.hh"
 #include "nix/store/s3.hh"
 #include "nix/util/compression.hh"
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index c2ecc4964..16865e39a 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -1,9 +1,9 @@
 #include "nix/store/globals.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/util/current-process.hh"
 #include "nix/util/archive.hh"
-#include "nix/util/args.hh"
-#include "nix/util/abstract-setting-to-json.hh"
+#include "nix/main/args.hh"
+#include "nix/main/abstract-setting-to-json.hh"
 #include "nix/util/compute-levels.hh"
 #include "nix/util/signals.hh"
 
@@ -29,7 +29,7 @@
 # include "nix/util/processes.hh"
 #endif
 
-#include "nix/util/config-impl.hh"
+#include "nix/main/config-impl.hh"
 
 #ifdef __APPLE__
 #include <sys/sysctl.h>
diff --git a/src/libstore/include/nix/store/config-parse-impl.hh b/src/libstore/include/nix/store/config-parse-impl.hh
index 1e7300c8f..a40528b1b 100644
--- a/src/libstore/include/nix/store/config-parse-impl.hh
+++ b/src/libstore/include/nix/store/config-parse-impl.hh
@@ -5,7 +5,7 @@
 
 #include "nix/store/config-parse.hh"
 #include "nix/util/util.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 
 namespace nix::config {
 
diff --git a/src/libstore/include/nix/store/derived-path.hh b/src/libstore/include/nix/store/derived-path.hh
index 64189bd41..7aad8c310 100644
--- a/src/libstore/include/nix/store/derived-path.hh
+++ b/src/libstore/include/nix/store/derived-path.hh
@@ -3,8 +3,8 @@
 
 #include "nix/store/path.hh"
 #include "nix/store/outputs-spec.hh"
-#include "nix/util/configuration.hh"
 #include "nix/util/ref.hh"
+#include "nix/util/experimental-feature-settings.hh"
 
 #include <variant>
 
diff --git a/src/libstore/include/nix/store/filetransfer.hh b/src/libstore/include/nix/store/filetransfer.hh
index 10c3ec7ef..dc586abef 100644
--- a/src/libstore/include/nix/store/filetransfer.hh
+++ b/src/libstore/include/nix/store/filetransfer.hh
@@ -7,7 +7,7 @@
 #include "nix/util/logging.hh"
 #include "nix/util/types.hh"
 #include "nix/util/ref.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/serialise.hh"
 
 namespace nix {
diff --git a/src/libstore/include/nix/store/globals.hh b/src/libstore/include/nix/store/globals.hh
index 3a677216a..335a456a8 100644
--- a/src/libstore/include/nix/store/globals.hh
+++ b/src/libstore/include/nix/store/globals.hh
@@ -7,7 +7,7 @@
 #include <sys/types.h>
 
 #include "nix/util/types.hh"
-#include "nix/util/configuration.hh"
+#include "nix/main/configuration.hh"
 #include "nix/util/environment-variables.hh"
 #include "nix/util/experimental-features.hh"
 #include "nix/util/users.hh"
diff --git a/src/libstore/unix/build/hook-instance.cc b/src/libstore/unix/build/hook-instance.cc
index 3713f7c86..894628e91 100644
--- a/src/libstore/unix/build/hook-instance.cc
+++ b/src/libstore/unix/build/hook-instance.cc
@@ -1,5 +1,5 @@
 #include "nix/store/globals.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/build/hook-instance.hh"
 #include "nix/util/file-system.hh"
 #include "nix/store/build/child.hh"
diff --git a/src/libutil-c/nix_api_util.cc b/src/libutil-c/nix_api_util.cc
index 2254f18fa..8664e3a89 100644
--- a/src/libutil-c/nix_api_util.cc
+++ b/src/libutil-c/nix_api_util.cc
@@ -1,5 +1,5 @@
 #include "nix_api_util.h"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/util/error.hh"
 #include "nix_api_util_internal.h"
 #include "nix/util/util.hh"
diff --git a/src/libutil-tests/args.cc b/src/libutil-tests/args.cc
index f5ad43a55..8c2c59281 100644
--- a/src/libutil-tests/args.cc
+++ b/src/libutil-tests/args.cc
@@ -1,4 +1,4 @@
-#include "nix/util/args.hh"
+#include "nix/main/args.hh"
 #include "nix/util/fs-sink.hh"
 #include <list>
 
diff --git a/src/libutil-tests/config.cc b/src/libutil-tests/config.cc
index bc7db251b..fa4c79dbb 100644
--- a/src/libutil-tests/config.cc
+++ b/src/libutil-tests/config.cc
@@ -1,5 +1,5 @@
-#include "nix/util/configuration.hh"
-#include "nix/util/args.hh"
+#include "nix/main/configuration.hh"
+#include "nix/main/args.hh"
 
 #include <sstream>
 #include <gtest/gtest.h>
diff --git a/src/libutil-tests/nix_api_util.cc b/src/libutil-tests/nix_api_util.cc
index baaaa81fc..4ef2c748b 100644
--- a/src/libutil-tests/nix_api_util.cc
+++ b/src/libutil-tests/nix_api_util.cc
@@ -1,5 +1,5 @@
-#include "nix/util/config-global.hh"
-#include "nix/util/args.hh"
+#include "nix/main/config-global.hh"
+#include "nix/main/args.hh"
 #include "nix_api_util.h"
 #include "nix_api_util_internal.h"
 #include "nix/util/tests/nix_api_util.hh"
diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc
index 9069e4b49..a9864a70f 100644
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@@ -6,7 +6,6 @@
 #include <strings.h> // for strcasecmp
 
 #include "nix/util/archive.hh"
-#include "nix/util/config-global.hh"
 #include "nix/util/posix-source-accessor.hh"
 #include "nix/util/source-path.hh"
 #include "nix/util/file-system.hh"
@@ -14,21 +13,19 @@
 
 namespace nix {
 
-struct ArchiveSettings : Config
-{
-    Setting<bool> useCaseHack{this,
-        #ifdef __APPLE__
-            true,
-        #else
-            false,
-        #endif
-        "use-case-hack",
-        "Whether to enable a macOS-specific hack for dealing with file name case collisions."};
+const extern ArchiveSettings<config::JustValue> archiveSettingsDefaults = {
+    .useCaseHack = {
+        .value =
+#ifdef __APPLE__
+            true
+#else
+            false
+#endif
+    },
 };
 
-static ArchiveSettings archiveSettings;
+ArchiveSettings<config::JustValue> archiveSettings = archiveSettingsDefaults;
 
-static GlobalConfig::Register rArchiveSettings(&archiveSettings);
 
 PathFilter defaultPathFilter = [](const Path &) { return true; };
 
diff --git a/src/libutil/experimental-feature-settings.cc b/src/libutil/experimental-feature-settings.cc
new file mode 100644
index 000000000..1b728e5b4
--- /dev/null
+++ b/src/libutil/experimental-feature-settings.cc
@@ -0,0 +1,37 @@
+#include "nix/util/experimental-feature-settings.hh"
+
+namespace nix {
+
+const extern ExperimentalFeatureSettings experimentalFeatureSettingsDefaults = {{
+    .experimentalFeatures =
+        {
+            .value = {},
+        },
+}};
+
+ExperimentalFeatureSettings experimentalFeatureSettings = experimentalFeatureSettingsDefaults;
+
+bool ExperimentalFeatureSettings::isEnabled(const ExperimentalFeature & feature) const
+{
+    auto & f = experimentalFeatures.get();
+    return std::find(f.begin(), f.end(), feature) != f.end();
+}
+
+void ExperimentalFeatureSettings::require(const ExperimentalFeature & feature) const
+{
+    if (!isEnabled(feature))
+        throw MissingExperimentalFeature(feature);
+}
+
+bool ExperimentalFeatureSettings::isEnabled(const std::optional<ExperimentalFeature> & feature) const
+{
+    return !feature || isEnabled(*feature);
+}
+
+void ExperimentalFeatureSettings::require(const std::optional<ExperimentalFeature> & feature) const
+{
+    if (feature)
+        require(*feature);
+}
+
+};
diff --git a/src/libutil/fs-sink.cc b/src/libutil/fs-sink.cc
index 7b8fc3b2a..92992c5e6 100644
--- a/src/libutil/fs-sink.cc
+++ b/src/libutil/fs-sink.cc
@@ -1,7 +1,6 @@
 #include <fcntl.h>
 
 #include "nix/util/error.hh"
-#include "nix/util/config-global.hh"
 #include "nix/util/fs-sink.hh"
 
 #ifdef _WIN32
@@ -62,15 +61,7 @@ void copyRecursive(
 }
 
 
-struct RestoreSinkSettings : Config
-{
-    Setting<bool> preallocateContents{this, false, "preallocate-contents",
-        "Whether to preallocate files when writing objects with known size."};
-};
-
-static RestoreSinkSettings restoreSinkSettings;
-
-static GlobalConfig::Register r1(&restoreSinkSettings);
+RestoreSinkSettings<config::JustValue> restoreSinkSettings;
 
 static std::filesystem::path append(const std::filesystem::path & src, const CanonPath & path)
 {
diff --git a/src/libutil/git.cc b/src/libutil/git.cc
index edeef71b7..5a545d187 100644
--- a/src/libutil/git.cc
+++ b/src/libutil/git.cc
@@ -6,7 +6,7 @@
 #include <strings.h> // for strcasecmp
 
 #include "nix/util/signals.hh"
-#include "nix/util/configuration.hh"
+#include "nix/util/config-abstract.hh"
 #include "nix/util/hash.hh"
 
 #include "nix/util/git.hh"
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index 015cc77a0..8dfce6b62 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -6,10 +6,9 @@
 #include <openssl/md5.h>
 #include <openssl/sha.h>
 
-#include "nix/util/args.hh"
 #include "nix/util/hash.hh"
 #include "nix/util/archive.hh"
-#include "nix/util/configuration.hh"
+#include "nix/util/experimental-feature-settings.hh"
 #include "nix/util/split.hh"
 
 #include <sys/types.h>
diff --git a/src/libutil/include/nix/util/archive.hh b/src/libutil/include/nix/util/archive.hh
index ae3274fa6..2c45872d4 100644
--- a/src/libutil/include/nix/util/archive.hh
+++ b/src/libutil/include/nix/util/archive.hh
@@ -2,12 +2,23 @@
 ///@file
 
 #include "nix/util/types.hh"
+#include "nix/util/config-abstract.hh"
 #include "nix/util/serialise.hh"
 #include "nix/util/fs-sink.hh"
 
 
 namespace nix {
 
+template<template<typename> class R>
+struct ArchiveSettings
+{
+    R<bool> useCaseHack;
+};
+
+const extern ArchiveSettings<config::JustValue> archiveSettingsDefaults;
+
+// FIXME: don't use a global variable.
+extern ArchiveSettings<config::JustValue> archiveSettings;
 
 /**
  * dumpPath creates a Nix archive of the specified path.
diff --git a/src/libutil/include/nix/util/experimental-feature-settings.hh b/src/libutil/include/nix/util/experimental-feature-settings.hh
new file mode 100644
index 000000000..f00277588
--- /dev/null
+++ b/src/libutil/include/nix/util/experimental-feature-settings.hh
@@ -0,0 +1,45 @@
+#pragma once
+///@file
+
+#include "nix/util/experimental-features.hh"
+
+namespace nix {
+
+template<template<typename> class R>
+struct ExperimentalFeatureSettingsT
+{
+    R<std::set<ExperimentalFeature>> experimentalFeatures;
+};
+
+struct ExperimentalFeatureSettings : ExperimentalFeatureSettingsT<config::JustValue>
+{
+    /**
+     * Check whether the given experimental feature is enabled.
+     */
+    bool isEnabled(const ExperimentalFeature &) const;
+
+    /**
+     * Require an experimental feature be enabled, throwing an error if it is
+     * not.
+     */
+    void require(const ExperimentalFeature &) const;
+
+    /**
+     * `std::nullopt` pointer means no feature, which means there is nothing that could be
+     * disabled, and so the function returns true in that case.
+     */
+    bool isEnabled(const std::optional<ExperimentalFeature> &) const;
+
+    /**
+     * `std::nullopt` pointer means no feature, which means there is nothing that could be
+     * disabled, and so the function does nothing in that case.
+     */
+    void require(const std::optional<ExperimentalFeature> &) const;
+};
+
+const extern ExperimentalFeatureSettings experimentalFeatureSettingsDefaults;
+
+// FIXME: don't use a global variable.
+extern ExperimentalFeatureSettings experimentalFeatureSettings;
+
+}
diff --git a/src/libutil/include/nix/util/experimental-features.hh b/src/libutil/include/nix/util/experimental-features.hh
index 8923517ba..29e52fa4c 100644
--- a/src/libutil/include/nix/util/experimental-features.hh
+++ b/src/libutil/include/nix/util/experimental-features.hh
@@ -1,6 +1,7 @@
 #pragma once
 ///@file
 
+#include "nix/util/config-abstract.hh"
 #include "nix/util/error.hh"
 #include "nix/util/types.hh"
 
diff --git a/src/libutil/include/nix/util/fs-sink.hh b/src/libutil/include/nix/util/fs-sink.hh
index 1c34fba93..b159e975a 100644
--- a/src/libutil/include/nix/util/fs-sink.hh
+++ b/src/libutil/include/nix/util/fs-sink.hh
@@ -1,12 +1,20 @@
 #pragma once
 ///@file
 
+#include "nix/util/config-abstract.hh"
 #include "nix/util/serialise.hh"
 #include "nix/util/source-accessor.hh"
 #include "nix/util/file-system.hh"
 
 namespace nix {
 
+template<template<typename> class R>
+struct RestoreSinkSettings
+{
+    R<bool> preallocateContents;
+};
+
+
 /**
  * Actions on an open regular file in the process of creating it.
  *
@@ -22,6 +30,8 @@ struct CreateRegularFileSink : Sink
     virtual void preallocateContents(uint64_t size) { };
 };
 
+// FIXME: don't use a global variable.
+extern RestoreSinkSettings<config::JustValue> restoreSinkSettings;
 
 struct FileSystemObjectSink
 {
diff --git a/src/libutil/include/nix/util/git.hh b/src/libutil/include/nix/util/git.hh
index 9bdb30bb9..50f9c017c 100644
--- a/src/libutil/include/nix/util/git.hh
+++ b/src/libutil/include/nix/util/git.hh
@@ -6,6 +6,7 @@
 #include <optional>
 
 #include "nix/util/types.hh"
+#include "nix/util/experimental-feature-settings.hh"
 #include "nix/util/serialise.hh"
 #include "nix/util/hash.hh"
 #include "nix/util/source-path.hh"
diff --git a/src/libutil/include/nix/util/hash.hh b/src/libutil/include/nix/util/hash.hh
index 0ae0a9564..08647d69b 100644
--- a/src/libutil/include/nix/util/hash.hh
+++ b/src/libutil/include/nix/util/hash.hh
@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "nix/util/configuration.hh"
+#include "nix/util/experimental-feature-settings.hh"
 #include "nix/util/types.hh"
 #include "nix/util/serialise.hh"
 #include "nix/util/file-system.hh"
diff --git a/src/libutil/include/nix/util/logging.hh b/src/libutil/include/nix/util/logging.hh
index 9210229bf..1129f0b33 100644
--- a/src/libutil/include/nix/util/logging.hh
+++ b/src/libutil/include/nix/util/logging.hh
@@ -2,7 +2,7 @@
 ///@file
 
 #include "nix/util/error.hh"
-#include "nix/util/configuration.hh"
+#include "nix/util/config-abstract.hh"
 #include "nix/util/file-descriptor.hh"
 #include "nix/util/finally.hh"
 
@@ -41,17 +41,13 @@ typedef enum {
 
 typedef uint64_t ActivityId;
 
-struct LoggerSettings : Config
+template<template<typename> class R>
+struct LoggerSettings
 {
-    Setting<bool> showTrace{
-        this, false, "show-trace",
-        R"(
-          Whether Nix should print out a stack trace in case of Nix
-          expression evaluation errors.
-        )"};
+    R<bool> showTrace;
 };
 
-extern LoggerSettings loggerSettings;
+extern LoggerSettings<config::JustValue> loggerSettings;
 
 class Logger
 {
diff --git a/src/libutil/include/nix/util/meson.build b/src/libutil/include/nix/util/meson.build
index d1a683e44..3690b5135 100644
--- a/src/libutil/include/nix/util/meson.build
+++ b/src/libutil/include/nix/util/meson.build
@@ -3,11 +3,8 @@
 include_dirs = [include_directories('../..')]
 
 headers = files(
-  'abstract-setting-to-json.hh',
   'ansicolor.hh',
   'archive.hh',
-  'args.hh',
-  'args/root.hh',
   'callback.hh',
   'canon-path.hh',
   'checked-arithmetic.hh',
@@ -17,9 +14,7 @@ headers = files(
   'compression.hh',
   'compute-levels.hh',
   'config-abstract.hh',
-  'config-global.hh',
-  'config-impl.hh',
-  'configuration.hh',
+  'config-abstract.hh',
   'current-process.hh',
   'english.hh',
   'environment-variables.hh',
diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index 1d0d3fa2d..507d3d4e4 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -3,7 +3,6 @@
 #include "nix/util/environment-variables.hh"
 #include "nix/util/terminal.hh"
 #include "nix/util/util.hh"
-#include "nix/util/config-global.hh"
 #include "nix/util/source-path.hh"
 #include "nix/util/position.hh"
 #include "nix/util/sync.hh"
@@ -15,9 +14,13 @@
 
 namespace nix {
 
-LoggerSettings loggerSettings;
+const extern LoggerSettings<config::JustValue> loggerSettingsDefaults = {
+    .showTrace = {
+        .value = false
+    },
+};
 
-static GlobalConfig::Register rLoggerSettings(&loggerSettings);
+LoggerSettings<config::JustValue> loggerSettings = loggerSettingsDefaults;
 
 static thread_local ActivityId curActivity = 0;
 
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index b0e82e46a..198d5d6e2 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -110,18 +110,16 @@ subdir('nix-meson-build-support/common')
 
 sources = [config_priv_h] + files(
   'archive.cc',
-  'args.cc',
   'canon-path.cc',
   'compression.cc',
   'compute-levels.cc',
-  'configuration.cc',
-  'config-global.cc',
   'current-process.cc',
   'english.cc',
   'environment-variables.cc',
   'error.cc',
   'executable-path.cc',
   'exit.cc',
+  'experimental-feature-settings.cc',
   'experimental-features.cc',
   'file-content-address.cc',
   'file-descriptor.cc',
diff --git a/src/nix/config.cc b/src/nix/config.cc
index cd82b08a6..2887a8a2f 100644
--- a/src/nix/config.cc
+++ b/src/nix/config.cc
@@ -2,7 +2,7 @@
 #include "nix/main/common-args.hh"
 #include "nix/main/shared.hh"
 #include "nix/store/store-api.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 
 #include <nlohmann/json.hpp>
 
diff --git a/src/nix/develop.cc b/src/nix/develop.cc
index 37bce6ca0..7569a1006 100644
--- a/src/nix/develop.cc
+++ b/src/nix/develop.cc
@@ -1,4 +1,4 @@
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/expr/eval.hh"
 #include "nix/cmd/installable-flake.hh"
 #include "nix/cmd/command-installable-value.hh"
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 551f1918a..05feee9e0 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -1,4 +1,4 @@
-#include "nix/util/args/root.hh"
+#include "nix/main/args/root.hh"
 #include "nix/util/current-process.hh"
 #include "nix/cmd/command.hh"
 #include "nix/main/common-args.hh"
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index ca470e99b..25b6d21b5 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -1,6 +1,6 @@
 #include "nix/expr/eval.hh"
 #include "nix/expr/eval-settings.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/globals.hh"
 #include "nix/store/store-open.hh"
 #include "nix/cmd/command.hh"
diff --git a/src/nix/unix/daemon.cc b/src/nix/unix/daemon.cc
index 98f302300..8a47aeae9 100644
--- a/src/nix/unix/daemon.cc
+++ b/src/nix/unix/daemon.cc
@@ -11,7 +11,7 @@
 #include "nix/util/serialise.hh"
 #include "nix/util/archive.hh"
 #include "nix/store/globals.hh"
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/store/derivations.hh"
 #include "nix/util/finally.hh"
 #include "nix/cmd/legacy.hh"
diff --git a/tests/functional/plugins/plugintest.cc b/tests/functional/plugins/plugintest.cc
index 0b1a01a6e..78ffde539 100644
--- a/tests/functional/plugins/plugintest.cc
+++ b/tests/functional/plugins/plugintest.cc
@@ -1,4 +1,4 @@
-#include "nix/util/config-global.hh"
+#include "nix/main/config-global.hh"
 #include "nix/expr/primops.hh"
 
 using namespace nix;