diff --git a/.gitignore b/.gitignore
index 15c871218..146d433a1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,5 +37,5 @@ buildtime.bin
 # Rust build files when using Cargo (not actually supported for building but it spews the files anyway)
 /target/
 
-# Python compiled files from the test suite
+# Python compiled files from the code generators and test suite
 *.pyc
diff --git a/doc/manual/generate-features-shortlist.nix b/doc/manual/generate-features-shortlist.nix
deleted file mode 100644
index 055698d64..000000000
--- a/doc/manual/generate-features-shortlist.nix
+++ /dev/null
@@ -1,14 +0,0 @@
-# Usually "experimental" or "deprecated"
-kind:
-# "xp" or "dp"
-kindShort:
-
-with builtins;
-with import ./utils.nix;
-
-let
-  showExperimentalFeature = name: doc: ''
-    - [`${name}`](@docroot@/contributing/${kind}-features.md#${kindShort}-feature-${name})
-  '';
-in
-xps: indent "  " (concatStrings (attrValues (mapAttrs showExperimentalFeature xps)))
diff --git a/doc/manual/generate-features.nix b/doc/manual/generate-features.nix
deleted file mode 100644
index 4a12ccdce..000000000
--- a/doc/manual/generate-features.nix
+++ /dev/null
@@ -1,18 +0,0 @@
-# Usually "experimental" or "deprecated"
-_kind:
-# "xp" or "dp"
-kindShort:
-
-with builtins;
-with import ./utils.nix;
-
-let
-  showFeature =
-    name: doc:
-    squash ''
-      ## [`${name}`]{#${kindShort}-feature-${name}}
-
-      ${doc}
-    '';
-in
-xps: (concatStringsSep "\n" (attrValues (mapAttrs showFeature xps)))
diff --git a/doc/manual/meson.build b/doc/manual/meson.build
index 35d94740c..02383f6bb 100644
--- a/doc/manual/meson.build
+++ b/doc/manual/meson.build
@@ -48,14 +48,6 @@ nix_conf_file_md = custom_target(
   output : 'conf-file.md',
 )
 
-nix_exp_features_json = custom_target(
-  command : [ nix, '__dump-xp-features' ],
-  capture : true,
-  output : 'xp-features.json',
-  # FIXME: put the actual lib targets in here? meson have introspection challenge 2024 though.
-  build_always_stale : true,
-)
-
 language_json = custom_target(
   command: [nix, '__dump-language'],
   output : 'language.json',
@@ -80,10 +72,8 @@ generate_manual_deps = files(
 
 # Generates builtins.md and builtin-constants.md.
 subdir('src/language')
-# Generates new-cli pages, {experimental,deprecated}-features-shortlist.md, and conf-file.md.
+# Generates new-cli pages  and conf-file.md.
 subdir('src/command-ref')
-# Generates {experimental,deprecated}-feature-descriptions.md.
-subdir('src/contributing')
 # Generates rl-next-generated.md.
 subdir('src/release-notes')
 
diff --git a/doc/manual/src/command-ref/meson.build b/doc/manual/src/command-ref/meson.build
index f66ee0d39..6acc79f4e 100644
--- a/doc/manual/src/command-ref/meson.build
+++ b/doc/manual/src/command-ref/meson.build
@@ -1,37 +1,3 @@
-experimental_features_shortlist_md = custom_target(
-  command : nix_eval_for_docs + [
-    '--expr',
-    'import @INPUT0@ "experimental" "xp" (builtins.fromJSON (builtins.readFile @INPUT1@))',
-  ],
-  input : [
-    '../../generate-features-shortlist.nix',
-    nix_exp_features_json,
-  ],
-  capture : true,
-  output : 'experimental-features-shortlist.md',
-  env : nix_env_for_docs,
-)
-
-dp_features_json = custom_target(
-  command : [nix, '__dump-dp-features'],
-  capture : true,
-  output : 'dp-features.json',
-)
-
-deprecated_features_shortlist_md = custom_target(
-  command : nix_eval_for_docs + [
-    '--expr',
-    'import @INPUT0@ "deprecated" "dp" (builtins.fromJSON (builtins.readFile @INPUT1@))',
-  ],
-  input : [
-    '../../generate-features-shortlist.nix',
-    dp_features_json,
-  ],
-  capture : true,
-  output : 'deprecated-features-shortlist.md',
-  env : nix_env_for_docs,
-)
-
 # Intermediate step for manpage generation.
 # This splorks the output of generate-manpage.nix as JSON,
 # which gets written as a directory tree below.
diff --git a/doc/manual/src/contributing/deprecated-features.md b/doc/manual/src/contributing/deprecated-features.md
index 7536944f7..ef37a1d98 100644
--- a/doc/manual/src/contributing/deprecated-features.md
+++ b/doc/manual/src/contributing/deprecated-features.md
@@ -34,4 +34,4 @@ However, we do not live in such an ideal world, and currently this goal is so fa
 
 # Currently available deprecated features
 
-{{#include @generated@/contributing/deprecated-feature-descriptions.md}}
+{{#include @generated@/../../../src/libutil/deprecated-feature-descriptions.md}}
diff --git a/doc/manual/src/contributing/experimental-features.md b/doc/manual/src/contributing/experimental-features.md
index c27ba5da0..d5f6f2526 100644
--- a/doc/manual/src/contributing/experimental-features.md
+++ b/doc/manual/src/contributing/experimental-features.md
@@ -99,4 +99,4 @@ This means that experimental features and RFCs are orthogonal mechanisms, and ca
 
 # Currently available experimental features
 
-{{#include @generated@/contributing/experimental-feature-descriptions.md}}
+{{#include @generated@/../../../src/libutil/experimental-feature-descriptions.md}}
diff --git a/doc/manual/src/contributing/hacking.md b/doc/manual/src/contributing/hacking.md
index 37c96a5c0..d245e20d1 100644
--- a/doc/manual/src/contributing/hacking.md
+++ b/doc/manual/src/contributing/hacking.md
@@ -399,3 +399,17 @@ The following properties are supported:
 
 Releases have a precomputed `rl-MAJOR.MINOR.md`, and no `rl-next.md`.
 Set `buildUnreleasedNotes = true;` in `flake.nix` to build the release notes on the fly.
+
+## Adding experimental or deprecated features
+
+Experimental and deprecated features are generally referenced both in the code and in the documentation.
+To prevent duplication or divergence, they are defined in data files, and a script generates the necessary glue.
+
+The data file format is similar to the release notes: it consists of a YAML metadata header, followed by the documentation in Markdown format.
+The following metadata properties are supported:
+* `name` (required): user-facing name of the feature, to be used in `nix.conf` options and on the command line.
+  This should also be the stem of the file name (with extension `md`).
+* `internalName` (required): identifier used to refer to the feature inside the C++ code.
+
+Experimental feature data files should live in `src/libutil/experimental-features`, and deprecated features in `src/libutil/deprecated-features`.
+They must be listed in the `experimental_feature_definitions` or `deprecated_feature_definitions` lists in `src/libutil/meson.build` respectively to be considered by the build system.
diff --git a/doc/manual/src/contributing/meson.build b/doc/manual/src/contributing/meson.build
deleted file mode 100644
index da88ca146..000000000
--- a/doc/manual/src/contributing/meson.build
+++ /dev/null
@@ -1,28 +0,0 @@
-# Intermediate step for experimental-feature-descriptions.md.
-# This splorks the output of generate-xp-features.nix as JSON,
-# which gets written as a directory tree below.
-experimental_feature_descriptions_md = custom_target(
-  command : nix_eval_for_docs + [
-    '--expr',
-    'import @INPUT0@ "experimental" "xp" (builtins.fromJSON (builtins.readFile @INPUT1@))',
-  ],
-  input : [
-    '../../generate-features.nix',
-    nix_exp_features_json,
-  ],
-  capture : true,
-  output : 'experimental-feature-descriptions.md',
-)
-
-deprecated_feature_descriptions_md = custom_target(
-  command : nix_eval_for_docs + [
-    '--expr',
-    'import @INPUT0@ "deprecated" "dp" (builtins.fromJSON (builtins.readFile @INPUT1@))',
-  ],
-  input : [
-    '../../generate-features.nix',
-    dp_features_json,
-  ],
-  capture : true,
-  output : 'deprecated-feature-descriptions.md',
-)
diff --git a/meson/clang-tidy/build_required_targets.py b/meson/clang-tidy/build_required_targets.py
index 5c0e9641e..f26aa24a5 100755
--- a/meson/clang-tidy/build_required_targets.py
+++ b/meson/clang-tidy/build_required_targets.py
@@ -14,7 +14,8 @@ def main():
 
     args = ap.parse_args()
 
-    targets = [t for t in get_targets_of_rule(args.build_root, 'CUSTOM_COMMAND') if t.endswith('gen.hh')]
+    targets = [t for t in get_targets_of_rule(args.build_root, 'CUSTOM_COMMAND') if t.endswith('.gen.hh')]
+    targets += [t for t in get_targets_of_rule(args.build_root, 'CUSTOM_COMMAND') if t.endswith('.gen.inc')]
     ninja_build(args.build_root, targets)
 
 if __name__ == '__main__':
diff --git a/package.nix b/package.nix
index 5c66b8446..297bc01fc 100644
--- a/package.nix
+++ b/package.nix
@@ -245,9 +245,11 @@ stdenv.mkDerivation (finalAttrs: {
 
   nativeBuildInputs =
     [
+      # python3.withPackages does not splice properly, see https://github.com/NixOS/nixpkgs/issues/305858
       (python3.pythonOnBuildForHost.withPackages (p: [
         p.pytest
         p.pytest-xdist
+        p.python-frontmatter
       ]))
       meson
       ninja
diff --git a/src/code-generation/build_experimental_features.py b/src/code-generation/build_experimental_features.py
new file mode 100644
index 000000000..8768d826e
--- /dev/null
+++ b/src/code-generation/build_experimental_features.py
@@ -0,0 +1,58 @@
+from typing import NamedTuple
+
+from common import cxx_literal, generate_file, load_data
+
+KNOWN_KEYS = set([
+    'name',
+    'internalName',
+])
+
+class ExperimentalFeature(NamedTuple):
+    name: str
+    internal_name: str
+    description: str
+
+    def parse(datum):
+        unknown_keys = set(datum.keys()) - KNOWN_KEYS
+        if unknown_keys:
+            raise ValueError('unknown keys', unknown_keys)
+        return ExperimentalFeature(
+            name = datum['name'],
+            internal_name = datum['internalName'],
+            description = datum.content,
+        )
+
+def main():
+    import argparse
+
+    ap = argparse.ArgumentParser()
+    ap.add_argument('--deprecated', action='store_true', help='Generate deprecated features')
+    ap.add_argument('--header', help='Path of the declaration header to generate')
+    ap.add_argument('--impl-header', help='Path of the implementation header to generate')
+    ap.add_argument('--descriptions', help='Path of the description file to generate')
+    ap.add_argument('--shortlist', help='Path of the shortlist file to generate')
+    ap.add_argument('defs', help='Experimental feature definition files', nargs='+')
+    args = ap.parse_args()
+
+    features = load_data(args.defs, ExperimentalFeature.parse)
+
+    generate_file(args.header, features, lambda feature: feature.name, lambda feature:
+        f'    {feature.internal_name},\n')
+    generate_file(args.impl_header, features, lambda feature: feature.name, lambda feature:
+        f'''    {{
+        .tag = {"Dep" if args.deprecated else "Xp"}::{feature.internal_name},
+        .name = {cxx_literal(feature.name)},
+        .description = {cxx_literal(feature.description)},
+    }},
+''')
+    generate_file(args.descriptions, features, lambda feature: feature.name, lambda feature:
+        f'''## [`{feature.name}`]{{#{"dp" if args.deprecated else "xp"}-feature-{feature.name}}}
+
+{feature.description}
+
+''')
+    generate_file(args.shortlist, features, lambda feature: feature.name, lambda feature:
+        f'  - [`{feature.name}`](@docroot@/contributing/{"deprecated" if args.deprecated else "experimental"}-features.md#{"dp" if args.deprecated else "xp"}-feature-{feature.name})\n')
+
+if __name__ == '__main__':
+    main()
diff --git a/src/code-generation/common.py b/src/code-generation/common.py
new file mode 100644
index 000000000..228359c78
--- /dev/null
+++ b/src/code-generation/common.py
@@ -0,0 +1,50 @@
+import frontmatter
+import pathlib
+from collections import defaultdict
+
+def cxx_escape_character(c):
+    if ord(c) >= 0x20 and ord(c) < 0x7f and c != '"' and c != '?' and c != '\\':
+        return c
+    elif c == '\t':
+        return r'\t'
+    elif c == '\n':
+        return r'\n'
+    elif c == '\r':
+        return r'\r'
+    elif c == '"':
+        return r'\"'
+    elif c == '?':
+        return r'\?'
+    elif c == '\\':
+        return r'\\'
+    elif ord(c) <= 0xffff:
+        return str.format(r'\u{:04x}', ord(c))
+    else:
+        return str.format(r'\U{:08x}', ord(c))
+
+def cxx_literal(v):
+    if isinstance(v, str):
+        return ''.join(['"', *(cxx_escape_character(c) for c in v), '"'])
+    else:
+        raise NotImplementedError(f'cannot represent {repr(v)} in C++')
+
+def load_data(defs, parse_function):
+    data = []
+    for path in defs:
+        try:
+            datum = frontmatter.load(path)
+            data.append((path, parse_function(datum)))
+        except Exception as e:
+            e.add_note(f'in {path}')
+            raise
+    return data
+
+def generate_file(path, data, sort_key_function, generate_function):
+    if path is not None:
+        with open(path, 'w') as out:
+            for path, datum in sorted(data, key=lambda pathAndDatum: sort_key_function(pathAndDatum[1])):
+                try:
+                    out.write(generate_function(datum))
+                except Exception as e:
+                    e.add_note(f'in {path}')
+                    raise
diff --git a/src/libutil/config.hh b/src/libutil/config.hh
index b3dcc122f..eadc71926 100644
--- a/src/libutil/config.hh
+++ b/src/libutil/config.hh
@@ -410,7 +410,7 @@ struct FeatureSettings : Config {
 
           The following experimental features are available:
 
-          {{#include @generated@/command-ref/experimental-features-shortlist.md}}
+          {{#include @generated@/../../../src/libutil/experimental-features-shortlist.md}}
 
           Experimental features are [further documented in the manual](@docroot@/contributing/experimental-features.md).
         )"};
@@ -450,7 +450,7 @@ struct FeatureSettings : Config {
 
           The following deprecated feature features can be re-activated:
 
-          {{#include @generated@/command-ref/deprecated-features-shortlist.md}}
+          {{#include @generated@/../../../src/libutil/deprecated-features-shortlist.md}}
 
           Deprecated features are [further documented in the manual](@docroot@/contributing/deprecated-features.md).
         )"};
diff --git a/src/libutil/deprecated-features.cc b/src/libutil/deprecated-features.cc
index 4de4c8ec7..65a003cd4 100644
--- a/src/libutil/deprecated-features.cc
+++ b/src/libutil/deprecated-features.cc
@@ -20,38 +20,13 @@ struct DeprecatedFeatureDetails
  * counter will be incremented once instead of twice, causing a build
  * failure.
  *
- * By instead defining this instead as 1 + the bottom deprecated
- * feature, we either have no issue at all if few features are not added
- * at the end of the list, or a proper merge conflict if they are.
+ * By instead defining this instead as a dummy bottom deprecated
+ * feature, we do not have this issue.
  */
-constexpr size_t numDepFeatures = 1 + static_cast<size_t>(Dep::UrlLiterals);
+constexpr size_t numDepFeatures = static_cast<size_t>(Dep::NumDepFeatures);
 
 constexpr std::array<DeprecatedFeatureDetails, numDepFeatures> depFeatureDetails = {{
-    {
-        .tag = Dep::RecSetOverrides,
-        .name = "rec-set-overrides",
-        .description = R"(
-            Allow `__overrides` in recursive attribute sets.
-
-            Use fix point functions (e.g. `lib.fix` in Nixpkgs) instead.
-        )",
-    },
-    {
-        .tag = Dep::AncientLet,
-        .name = "ancient-let",
-        .description = R"(
-            Allow the ancient `let { body = …; … }` syntax.
-
-            Use the `let … in` syntax instead.
-        )",
-    },
-    {
-        .tag = Dep::UrlLiterals,
-        .name = "url-literals",
-        .description = R"(
-            Allow unquoted URLs as part of the Nix language syntax.
-        )",
-    },
+    #include "deprecated-features-impl.gen.inc"
 }};
 
 static_assert(
diff --git a/src/libutil/deprecated-features.hh b/src/libutil/deprecated-features.hh
index bdff1bcdb..cd425e8f7 100644
--- a/src/libutil/deprecated-features.hh
+++ b/src/libutil/deprecated-features.hh
@@ -9,18 +9,13 @@ namespace nix {
 /**
  * The list of available deprecated features.
  *
- * If you update this, don’t forget to also change the map defining
- * their string representation and documentation in the corresponding
- * `.cc` file as well.
- *
  * Reminder: New deprecated features should start out with a warning without throwing an error.
  * See the developer documentation for details.
  */
 enum struct DeprecatedFeature
 {
-    RecSetOverrides,
-    AncientLet,
-    UrlLiterals,
+    #include "deprecated-features.gen.inc"
+    NumDepFeatures, // number of available deprecated features, do not use
 };
 
 enum struct DeprecatedFeatures {};
diff --git a/src/libutil/deprecated-features/ancient-let.md b/src/libutil/deprecated-features/ancient-let.md
new file mode 100644
index 000000000..ced9934bb
--- /dev/null
+++ b/src/libutil/deprecated-features/ancient-let.md
@@ -0,0 +1,7 @@
+---
+name: ancient-let
+internalName: AncientLet
+---
+Allow the ancient `let { body = …; … }` syntax.
+
+Use the `let … in` syntax instead.
diff --git a/src/libutil/deprecated-features/rec-set-overrides.md b/src/libutil/deprecated-features/rec-set-overrides.md
new file mode 100644
index 000000000..37d7003b1
--- /dev/null
+++ b/src/libutil/deprecated-features/rec-set-overrides.md
@@ -0,0 +1,7 @@
+---
+name: rec-set-overrides
+internalName: RecSetOverrides
+---
+Allow `__overrides` in recursive attribute sets.
+
+Use fix point functions (e.g. `lib.fix` in Nixpkgs) instead.
diff --git a/src/libutil/deprecated-features/url-literals.md b/src/libutil/deprecated-features/url-literals.md
new file mode 100644
index 000000000..99232913f
--- /dev/null
+++ b/src/libutil/deprecated-features/url-literals.md
@@ -0,0 +1,5 @@
+---
+name: url-literals
+internalName: UrlLiterals
+---
+Allow unquoted URLs as part of the Nix language syntax.
diff --git a/src/libutil/experimental-features.cc b/src/libutil/experimental-features.cc
index bb7a95a24..da3e6c2cd 100644
--- a/src/libutil/experimental-features.cc
+++ b/src/libutil/experimental-features.cc
@@ -20,236 +20,13 @@ struct ExperimentalFeatureDetails
  * counter will be incremented once instead of twice, causing a build
  * failure.
  *
- * By instead defining this instead as 1 + the bottom experimental
- * feature, we either have no issue at all if few features are not added
- * at the end of the list, or a proper merge conflict if they are.
+ * By instead defining this instead as a dummy bottom experimental
+ * feature, we do not get this issue.
  */
-constexpr size_t numXpFeatures = 1 + static_cast<size_t>(Xp::ReplAutomation);
+constexpr size_t numXpFeatures = static_cast<size_t>(Xp::NumXpFeatures);
 
 constexpr std::array<ExperimentalFeatureDetails, numXpFeatures> xpFeatureDetails = {{
-    {
-        .tag = Xp::CaDerivations,
-        .name = "ca-derivations",
-        .description = R"(
-            Allow derivations to be content-addressed in order to prevent
-            rebuilds when changes to the derivation do not result in changes to
-            the derivation's output. See
-            [__contentAddressed](@docroot@/language/advanced-attributes.md#adv-attr-__contentAddressed)
-            for details.
-        )",
-    },
-    {
-        .tag = Xp::ImpureDerivations,
-        .name = "impure-derivations",
-        .description = R"(
-            Allow derivations to produce non-fixed outputs by setting the
-            `__impure` derivation attribute to `true`. An impure derivation can
-            have differing outputs each time it is built.
-
-            Example:
-
-            ```
-            derivation {
-              name = "impure";
-              builder = /bin/sh;
-              __impure = true; # mark this derivation as impure
-              args = [ "-c" "read -n 10 random < /dev/random; echo $random > $out" ];
-              system = builtins.currentSystem;
-            }
-            ```
-
-            Each time this derivation is built, it can produce a different
-            output (as the builder outputs random bytes to `$out`).  Impure
-            derivations also have access to the network, and only fixed-output
-            or other impure derivations can rely on impure derivations. Finally,
-            an impure derivation cannot also be
-            [content-addressed](#xp-feature-ca-derivations).
-
-            This is a more explicit alternative to using [`builtins.currentTime`](@docroot@/language/builtin-constants.md#builtins-currentTime).
-        )",
-    },
-    {
-        .tag = Xp::Flakes,
-        .name = "flakes",
-        .description = R"(
-            Enable flakes. See the manual entry for [`nix
-            flake`](@docroot@/command-ref/new-cli/nix3-flake.md) for details.
-        )",
-    },
-    {
-        .tag = Xp::NixCommand,
-        .name = "nix-command",
-        .description = R"(
-            Enable the new `nix` subcommands. See the manual on
-            [`nix`](@docroot@/command-ref/new-cli/nix.md) for details.
-        )",
-    },
-    {
-        .tag = Xp::RecursiveNix,
-        .name = "recursive-nix",
-        .description = R"(
-            Allow derivation builders to call Nix, and thus build derivations
-            recursively.
-
-            Example:
-
-            ```
-            with import <nixpkgs> {};
-
-            runCommand "foo"
-              {
-                 buildInputs = [ nix jq ];
-                 NIX_PATH = "nixpkgs=${<nixpkgs>}";
-              }
-              ''
-                hello=$(nix-build -E '(import <nixpkgs> {}).hello.overrideDerivation (args: { name = "recursive-hello"; })')
-
-                mkdir -p $out/bin
-                ln -s $hello/bin/hello $out/bin/hello
-              ''
-            ```
-
-            An important restriction on recursive builders is disallowing
-            arbitrary substitutions. For example, running
-
-            ```
-            nix-store -r /nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10
-            ```
-
-            in the above `runCommand` script would be disallowed, as this could
-            lead to derivations with hidden dependencies or breaking
-            reproducibility by relying on the current state of the Nix store. An
-            exception would be if
-            `/nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10` were
-            already in the build inputs or built by a previous recursive Nix
-            call.
-        )",
-    },
-    {
-        .tag = Xp::NoUrlLiterals,
-        .name = "no-url-literals",
-        .description = R"(
-            Disallow unquoted URLs as part of the Nix language syntax. The Nix
-            language allows for URL literals, like so:
-
-            ```
-            $ nix repl
-            Welcome to Nix 2.15.0. Type :? for help.
-
-            nix-repl> http://foo
-            "http://foo"
-            ```
-
-            But enabling this experimental feature will cause the Nix parser to
-            throw an error when encountering a URL literal:
-
-            ```
-            $ nix repl --extra-experimental-features 'no-url-literals'
-            Welcome to Nix 2.15.0. Type :? for help.
-
-            nix-repl> http://foo
-            error: URL literals are disabled
-
-            at «string»:1:1:
-
-            1| http://foo
-             | ^
-
-            ```
-
-            While this is currently an experimental feature, unquoted URLs are
-            being deprecated and their usage is discouraged.
-
-            The reason is that, as opposed to path literals, URLs have no
-            special properties that distinguish them from regular strings, URLs
-            containing parameters have to be quoted anyway, and unquoted URLs
-            may confuse external tooling.
-        )",
-    },
-    {
-        .tag = Xp::PipeOperator,
-        .name = "pipe-operator",
-        .description = R"(
-            Enable new operators for function application to "pipe" arguments through a chain of functions similar to `lib.pipe`.
-            This implementation is based on Nix [RFC 148](https://github.com/NixOS/rfcs/pull/148).
-
-            Tracking issue: https://git.lix.systems/lix-project/lix/issues/438
-        )",
-    },
-    {
-        .tag = Xp::FetchClosure,
-        .name = "fetch-closure",
-        .description = R"(
-            Enable the use of the [`fetchClosure`](@docroot@/language/builtins.md#builtins-fetchClosure) built-in function in the Nix language.
-        )",
-    },
-    {
-        .tag = Xp::ReplFlake,
-        .name = "repl-flake",
-        .description = R"(
-            Allow passing [installables](@docroot@/command-ref/new-cli/nix.md#installables) to `nix repl`, making its interface consistent with the other experimental commands.
-        )",
-    },
-    {
-        .tag = Xp::AutoAllocateUids,
-        .name = "auto-allocate-uids",
-        .description = R"(
-            Allows Nix to automatically pick UIDs for builds, rather than creating
-            `nixbld*` user accounts. See the [`auto-allocate-uids`](#conf-auto-allocate-uids) setting for details.
-        )",
-    },
-    {
-        .tag = Xp::Cgroups,
-        .name = "cgroups",
-        .description = R"(
-            Allows Nix to execute builds inside cgroups. See
-            the [`use-cgroups`](#conf-use-cgroups) setting for details.
-        )",
-    },
-    {
-        .tag = Xp::DaemonTrustOverride,
-        .name = "daemon-trust-override",
-        .description = R"(
-            Allow forcing trusting or not trusting clients with
-            `nix-daemon`. This is useful for testing, but possibly also
-            useful for various experiments with `nix-daemon --stdio`
-            networking.
-        )",
-    },
-    {
-        .tag = Xp::DynamicDerivations,
-        .name = "dynamic-derivations",
-        .description = R"(
-            Allow the use of a few things related to dynamic derivations:
-
-              - "text hashing" derivation outputs, so we can build .drv
-                files.
-
-              - dependencies in derivations on the outputs of
-                derivations that are themselves derivations outputs.
-        )",
-    },
-    {
-        .tag = Xp::ParseTomlTimestamps,
-        .name = "parse-toml-timestamps",
-        .description = R"(
-            Allow parsing of timestamps in builtins.fromTOML.
-        )",
-    },
-    {
-        .tag = Xp::ReadOnlyLocalStore,
-        .name = "read-only-local-store",
-        .description = R"(
-            Allow the use of the `read-only` parameter in [local store](@docroot@/command-ref/new-cli/nix3-help-stores.md#local-store) URIs.
-        )",
-    },
-    {
-        .tag = Xp::ReplAutomation,
-        .name = "repl-automation",
-        .description = R"(
-            Makes the repl not use editline, print ENQ (U+0005) when ready for a command, and take commands followed by newline.
-        )",
-    },
+    #include "experimental-features-impl.gen.inc"
 }};
 
 static_assert(
diff --git a/src/libutil/experimental-features.hh b/src/libutil/experimental-features.hh
index c45f05d78..3241ed955 100644
--- a/src/libutil/experimental-features.hh
+++ b/src/libutil/experimental-features.hh
@@ -8,29 +8,11 @@ namespace nix {
 
 /**
  * The list of available experimental features.
- *
- * If you update this, don’t forget to also change the map defining
- * their string representation and documentation in the corresponding
- * `.cc` file as well.
  */
 enum struct ExperimentalFeature
 {
-    CaDerivations,
-    ImpureDerivations,
-    Flakes,
-    NixCommand,
-    RecursiveNix,
-    NoUrlLiterals,
-    PipeOperator,
-    FetchClosure,
-    ReplFlake,
-    AutoAllocateUids,
-    Cgroups,
-    DaemonTrustOverride,
-    DynamicDerivations,
-    ParseTomlTimestamps,
-    ReadOnlyLocalStore,
-    ReplAutomation,
+    #include "experimental-features.gen.inc"
+    NumXpFeatures, // number of available experimental features, do not use
 };
 
 enum struct ExperimentalFeatures {};
diff --git a/src/libutil/experimental-features/auto-allocate-uids.md b/src/libutil/experimental-features/auto-allocate-uids.md
new file mode 100644
index 000000000..af7a2b68d
--- /dev/null
+++ b/src/libutil/experimental-features/auto-allocate-uids.md
@@ -0,0 +1,6 @@
+---
+name: auto-allocate-uids
+internalName: AutoAllocateUids
+---
+Allows Nix to automatically pick UIDs for builds, rather than creating
+`nixbld*` user accounts. See the [`auto-allocate-uids`](#conf-auto-allocate-uids) setting for details.
diff --git a/src/libutil/experimental-features/ca-derivations.md b/src/libutil/experimental-features/ca-derivations.md
new file mode 100644
index 000000000..423666c54
--- /dev/null
+++ b/src/libutil/experimental-features/ca-derivations.md
@@ -0,0 +1,9 @@
+---
+name: ca-derivations
+internalName: CaDerivations
+---
+Allow derivations to be content-addressed in order to prevent
+rebuilds when changes to the derivation do not result in changes to
+the derivation's output. See
+[__contentAddressed](@docroot@/language/advanced-attributes.md#adv-attr-__contentAddressed)
+for details.
diff --git a/src/libutil/experimental-features/cgroups.md b/src/libutil/experimental-features/cgroups.md
new file mode 100644
index 000000000..66e64fde9
--- /dev/null
+++ b/src/libutil/experimental-features/cgroups.md
@@ -0,0 +1,6 @@
+---
+name: cgroups
+internalName: Cgroups
+---
+Allows Nix to execute builds inside cgroups. See
+the [`use-cgroups`](#conf-use-cgroups) setting for details.
diff --git a/src/libutil/experimental-features/daemon-trust-override.md b/src/libutil/experimental-features/daemon-trust-override.md
new file mode 100644
index 000000000..e87f31dd3
--- /dev/null
+++ b/src/libutil/experimental-features/daemon-trust-override.md
@@ -0,0 +1,8 @@
+---
+name: daemon-trust-override
+internalName: DaemonTrustOverride
+---
+Allow forcing trusting or not trusting clients with
+`nix-daemon`. This is useful for testing, but possibly also
+useful for various experiments with `nix-daemon --stdio`
+networking.
diff --git a/src/libutil/experimental-features/dynamic-derivations.md b/src/libutil/experimental-features/dynamic-derivations.md
new file mode 100644
index 000000000..79201bcc3
--- /dev/null
+++ b/src/libutil/experimental-features/dynamic-derivations.md
@@ -0,0 +1,11 @@
+---
+name: dynamic-derivations
+internalName: DynamicDerivations
+---
+Allow the use of a few things related to dynamic derivations:
+
+  - "text hashing" derivation outputs, so we can build .drv
+    files.
+
+  - dependencies in derivations on the outputs of
+    derivations that are themselves derivations outputs.
diff --git a/src/libutil/experimental-features/fetch-closure.md b/src/libutil/experimental-features/fetch-closure.md
new file mode 100644
index 000000000..45692f030
--- /dev/null
+++ b/src/libutil/experimental-features/fetch-closure.md
@@ -0,0 +1,5 @@
+---
+name: fetch-closure
+internalName: FetchClosure
+---
+Enable the use of the [`fetchClosure`](@docroot@/language/builtins.md#builtins-fetchClosure) built-in function in the Nix language.
diff --git a/src/libutil/experimental-features/flakes.md b/src/libutil/experimental-features/flakes.md
new file mode 100644
index 000000000..3cb1c74a0
--- /dev/null
+++ b/src/libutil/experimental-features/flakes.md
@@ -0,0 +1,6 @@
+---
+name: flakes
+internalName: Flakes
+---
+Enable flakes. See the manual entry for [`nix
+flake`](@docroot@/command-ref/new-cli/nix3-flake.md) for details.
diff --git a/src/libutil/experimental-features/impure-derivations.md b/src/libutil/experimental-features/impure-derivations.md
new file mode 100644
index 000000000..f2ab9f5f2
--- /dev/null
+++ b/src/libutil/experimental-features/impure-derivations.md
@@ -0,0 +1,28 @@
+---
+name: impure-derivations
+internalName: ImpureDerivations
+---
+Allow derivations to produce non-fixed outputs by setting the
+`__impure` derivation attribute to `true`. An impure derivation can
+have differing outputs each time it is built.
+
+Example:
+
+```
+derivation {
+  name = "impure";
+  builder = /bin/sh;
+  __impure = true; # mark this derivation as impure
+  args = [ "-c" "read -n 10 random < /dev/random; echo $random > $out" ];
+  system = builtins.currentSystem;
+}
+```
+
+Each time this derivation is built, it can produce a different
+output (as the builder outputs random bytes to `$out`).  Impure
+derivations also have access to the network, and only fixed-output
+or other impure derivations can rely on impure derivations. Finally,
+an impure derivation cannot also be
+[content-addressed](#xp-feature-ca-derivations).
+
+This is a more explicit alternative to using [`builtins.currentTime`](@docroot@/language/builtin-constants.md#builtins-currentTime).
diff --git a/src/libutil/experimental-features/nix-command.md b/src/libutil/experimental-features/nix-command.md
new file mode 100644
index 000000000..7cfe6a97f
--- /dev/null
+++ b/src/libutil/experimental-features/nix-command.md
@@ -0,0 +1,6 @@
+---
+name: nix-command
+internalName: NixCommand
+---
+Enable the new `nix` subcommands. See the manual on
+[`nix`](@docroot@/command-ref/new-cli/nix.md) for details.
diff --git a/src/libutil/experimental-features/no-url-literals.md b/src/libutil/experimental-features/no-url-literals.md
new file mode 100644
index 000000000..2c183900e
--- /dev/null
+++ b/src/libutil/experimental-features/no-url-literals.md
@@ -0,0 +1,39 @@
+---
+name: no-url-literals
+internalName: NoUrlLiterals
+---
+Disallow unquoted URLs as part of the Nix language syntax. The Nix
+language allows for URL literals, like so:
+
+```
+$ nix repl
+Welcome to Nix 2.15.0. Type :? for help.
+
+nix-repl> http://foo
+"http://foo"
+```
+
+But enabling this experimental feature will cause the Nix parser to
+throw an error when encountering a URL literal:
+
+```
+$ nix repl --extra-experimental-features 'no-url-literals'
+Welcome to Nix 2.15.0. Type :? for help.
+
+nix-repl> http://foo
+error: URL literals are disabled
+
+at «string»:1:1:
+
+1| http://foo
+ | ^
+
+```
+
+While this is currently an experimental feature, unquoted URLs are
+being deprecated and their usage is discouraged.
+
+The reason is that, as opposed to path literals, URLs have no
+special properties that distinguish them from regular strings, URLs
+containing parameters have to be quoted anyway, and unquoted URLs
+may confuse external tooling.
diff --git a/src/libutil/experimental-features/parse-toml-timestamps.md b/src/libutil/experimental-features/parse-toml-timestamps.md
new file mode 100644
index 000000000..9dbfb70d0
--- /dev/null
+++ b/src/libutil/experimental-features/parse-toml-timestamps.md
@@ -0,0 +1,5 @@
+---
+name: parse-toml-timestamps
+internalName: ParseTomlTimestamps
+---
+Allow parsing of timestamps in builtins.fromTOML.
diff --git a/src/libutil/experimental-features/pipe-operator.md b/src/libutil/experimental-features/pipe-operator.md
new file mode 100644
index 000000000..c9f26ffa3
--- /dev/null
+++ b/src/libutil/experimental-features/pipe-operator.md
@@ -0,0 +1,8 @@
+---
+name: pipe-operator
+internalName: PipeOperator
+---
+Enable new operators for function application to "pipe" arguments through a chain of functions similar to `lib.pipe`.
+This implementation is based on Nix [RFC 148](https://github.com/NixOS/rfcs/pull/148).
+
+Tracking issue: https://git.lix.systems/lix-project/lix/issues/438
diff --git a/src/libutil/experimental-features/read-only-local-store.md b/src/libutil/experimental-features/read-only-local-store.md
new file mode 100644
index 000000000..700618765
--- /dev/null
+++ b/src/libutil/experimental-features/read-only-local-store.md
@@ -0,0 +1,5 @@
+---
+name: read-only-local-store
+internalName: ReadOnlyLocalStore
+---
+Allow the use of the `read-only` parameter in [local store](@docroot@/command-ref/new-cli/nix3-help-stores.md#local-store) URIs.
diff --git a/src/libutil/experimental-features/recursive-nix.md b/src/libutil/experimental-features/recursive-nix.md
new file mode 100644
index 000000000..fd67ed5aa
--- /dev/null
+++ b/src/libutil/experimental-features/recursive-nix.md
@@ -0,0 +1,39 @@
+---
+name: recursive-nix
+internalName: RecursiveNix
+---
+Allow derivation builders to call Nix, and thus build derivations
+recursively.
+
+Example:
+
+```
+with import <nixpkgs> {};
+
+runCommand "foo"
+  {
+     buildInputs = [ nix jq ];
+     NIX_PATH = "nixpkgs=${<nixpkgs>}";
+  }
+  ''
+    hello=$(nix-build -E '(import <nixpkgs> {}).hello.overrideDerivation (args: { name = "recursive-hello"; })')
+
+    mkdir -p $out/bin
+    ln -s $hello/bin/hello $out/bin/hello
+  ''
+```
+
+An important restriction on recursive builders is disallowing
+arbitrary substitutions. For example, running
+
+```
+nix-store -r /nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10
+```
+
+in the above `runCommand` script would be disallowed, as this could
+lead to derivations with hidden dependencies or breaking
+reproducibility by relying on the current state of the Nix store. An
+exception would be if
+`/nix/store/kmwd1hq55akdb9sc7l3finr175dajlby-hello-2.10` were
+already in the build inputs or built by a previous recursive Nix
+call.
diff --git a/src/libutil/experimental-features/repl-automation.md b/src/libutil/experimental-features/repl-automation.md
new file mode 100644
index 000000000..c21cd4478
--- /dev/null
+++ b/src/libutil/experimental-features/repl-automation.md
@@ -0,0 +1,5 @@
+---
+name: repl-automation
+internalName: ReplAutomation
+---
+Makes the repl not use editline, print ENQ (U+0005) when ready for a command, and take commands followed by newline.
diff --git a/src/libutil/experimental-features/repl-flake.md b/src/libutil/experimental-features/repl-flake.md
new file mode 100644
index 000000000..76d910bbf
--- /dev/null
+++ b/src/libutil/experimental-features/repl-flake.md
@@ -0,0 +1,5 @@
+---
+name: repl-flake
+internalName: ReplFlake
+---
+Allow passing [installables](@docroot@/command-ref/new-cli/nix.md#installables) to `nix repl`, making its interface consistent with the other experimental commands.
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index afca4e021..ca75df2d5 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -130,9 +130,99 @@ libutil_headers = files(
   'xml-writer.hh',
 )
 
+experimental_feature_definitions = files(
+  'experimental-features/auto-allocate-uids.md',
+  'experimental-features/ca-derivations.md',
+  'experimental-features/cgroups.md',
+  'experimental-features/daemon-trust-override.md',
+  'experimental-features/dynamic-derivations.md',
+  'experimental-features/fetch-closure.md',
+  'experimental-features/flakes.md',
+  'experimental-features/impure-derivations.md',
+  'experimental-features/nix-command.md',
+  'experimental-features/no-url-literals.md',
+  'experimental-features/parse-toml-timestamps.md',
+  'experimental-features/pipe-operator.md',
+  'experimental-features/read-only-local-store.md',
+  'experimental-features/recursive-nix.md',
+  'experimental-features/repl-automation.md',
+  'experimental-features/repl-flake.md',
+)
+
+deprecated_feature_definitions = files(
+  'deprecated-features/ancient-let.md',
+  'deprecated-features/rec-set-overrides.md',
+  'deprecated-features/url-literals.md',
+)
+
+experimental_features_gen = custom_target(
+  command : [
+    python.full_path(),
+    '@SOURCE_ROOT@/src/code-generation/build_experimental_features.py',
+    '--header', '@OUTPUT0@',
+    '--impl-header', '@OUTPUT1@',
+    '--shortlist', '@OUTPUT2@',
+    '--descriptions', '@OUTPUT3@',
+    '@INPUT@',
+  ],
+  input : experimental_feature_definitions,
+  output : [
+    'experimental-features.gen.inc',
+    'experimental-features-impl.gen.inc',
+    'experimental-features-shortlist.md',
+    'experimental-feature-descriptions.md',
+  ],
+  install : true,
+  install_dir: [
+    includedir / 'lix/libutil',
+    false,
+    false,
+    false,
+  ],
+)
+experimental_features_header = experimental_features_gen[0]
+experimental_features_impl_header = experimental_features_gen[1]
+experimental_features_shortlist_md = experimental_features_gen[2]
+experimental_feature_descriptions_md = experimental_features_gen[3]
+
+deprecated_features_gen = custom_target(
+  command : [
+    python.full_path(),
+    '@SOURCE_ROOT@/src/code-generation/build_experimental_features.py',
+    '--deprecated',
+    '--header', '@OUTPUT0@',
+    '--impl-header', '@OUTPUT1@',
+    '--shortlist', '@OUTPUT2@',
+    '--descriptions', '@OUTPUT3@',
+    '@INPUT@',
+  ],
+  input : deprecated_feature_definitions,
+  output : [
+    'deprecated-features.gen.inc',
+    'deprecated-features-impl.gen.inc',
+    'deprecated-features-shortlist.md',
+    'deprecated-feature-descriptions.md',
+  ],
+  install : true,
+  install_dir: [
+    includedir / 'lix/libutil',
+    false,
+    false,
+    false
+  ],
+)
+deprecated_features_header = deprecated_features_gen[0]
+deprecated_features_impl_header = deprecated_features_gen[1]
+deprecated_features_shortlist_md = deprecated_features_gen[2]
+deprecated_feature_descriptions_md = deprecated_features_gen[3]
+
 libutil = library(
   'lixutil',
   libutil_sources,
+  experimental_features_header,
+  experimental_features_impl_header,
+  deprecated_features_header,
+  deprecated_features_impl_header,
   dependencies : [
     aws_sdk,
     aws_s3,
@@ -169,6 +259,10 @@ configure_file(
 # Used by libstore and libfetchers.
 liblixutil = declare_dependency(
   include_directories : include_directories('.'),
+  sources : [
+    experimental_features_header,
+    deprecated_features_header,
+  ],
   link_with : libutil
 )
 
@@ -176,6 +270,10 @@ liblixutil = declare_dependency(
 if is_static
   liblixutil_mstatic = declare_dependency(
     include_directories : include_directories('.'),
+    sources : [
+      experimental_features_header,
+      deprecated_features_header,
+    ],
     link_whole : libutil,
   )
 else