diff --git a/rs_bindings_from_cc/BUILD b/rs_bindings_from_cc/BUILD
index 73a956e..51e1db4 100644
--- a/rs_bindings_from_cc/BUILD
+++ b/rs_bindings_from_cc/BUILD
@@ -169,6 +169,7 @@
         ":cc_ir",
         "//common:status_macros",
         "@absl//absl/container:flat_hash_map",
+        "@absl//absl/container:flat_hash_set",
         "@absl//absl/flags:flag",
         "@absl//absl/log",
         "@absl//absl/status:statusor",
@@ -302,6 +303,7 @@
     srcs = ["ir.rs"],
     deps = [
         "//common:arc_anyhow",
+        "@crate_index//:flagset",
         "@crate_index//:itertools",
         "@crate_index//:once_cell",
         "@crate_index//:proc-macro2",
@@ -338,6 +340,7 @@
         ":cc_ir",
         ":frontend_action",
         "@absl//absl/container:flat_hash_map",
+        "@absl//absl/container:flat_hash_set",
         "@absl//absl/log:check",
         "@absl//absl/status",
         "@absl//absl/status:statusor",
@@ -402,6 +405,7 @@
         "//common:code_gen_utils",
         "//common:ffi_types",
         "//common:token_stream_printer",
+        "@crate_index//:flagset",
         "@crate_index//:itertools",
         "@crate_index//:once_cell",
         "@crate_index//:proc-macro2",
diff --git a/rs_bindings_from_cc/cmdline.cc b/rs_bindings_from_cc/cmdline.cc
index 5b89bf3..4305344 100644
--- a/rs_bindings_from_cc/cmdline.cc
+++ b/rs_bindings_from_cc/cmdline.cc
@@ -87,13 +87,15 @@
 struct TargetArgs {
   std::string target;
   std::vector<std::string> headers;
+  std::vector<std::string> features;
 };
 
 bool fromJSON(const llvm::json::Value& json, TargetArgs& out,
               llvm::json::Path path) {
   llvm::json::ObjectMapper mapper(json, path);
   return mapper && mapper.map("t", out.target) &&
-         mapper.mapOptional("h", out.headers);
+         mapper.mapOptional("h", out.headers) &&
+         mapper.mapOptional("f", out.features);
 }
 
 }  // namespace
@@ -216,6 +218,14 @@
         }
       }
     }
+    for (const std::string& feature : it.features) {
+      if (feature.empty()) {
+        return absl::InvalidArgumentError(
+            "Expected `f` (feature) fields of `--target_args` to be an "
+            "array of non-empty strings");
+      }
+      cmdline.target_to_features_[BazelLabel(target)].insert(feature);
+    }
   }
 
   for (const HeaderName& public_header : cmdline.public_headers_) {
diff --git a/rs_bindings_from_cc/cmdline.h b/rs_bindings_from_cc/cmdline.h
index 6d557dc..8eb3b7e 100644
--- a/rs_bindings_from_cc/cmdline.h
+++ b/rs_bindings_from_cc/cmdline.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "absl/container/flat_hash_map.h"
+#include "absl/container/flat_hash_set.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
 #include "rs_bindings_from_cc/bazel_types.h"
@@ -82,6 +83,11 @@
     return headers_to_targets_;
   }
 
+  const absl::flat_hash_map<BazelLabel, absl::flat_hash_set<std::string>>&
+  target_to_features() const {
+    return target_to_features_;
+  }
+
  private:
   Cmdline();
 
@@ -117,6 +123,8 @@
   std::string instantiations_out_;
 
   std::string namespaces_out_;
+  absl::flat_hash_map<BazelLabel, absl::flat_hash_set<std::string>>
+      target_to_features_;
 };
 
 }  // namespace crubit
diff --git a/rs_bindings_from_cc/cmdline_test.cc b/rs_bindings_from_cc/cmdline_test.cc
index 61063fd..97fef2b 100644
--- a/rs_bindings_from_cc/cmdline_test.cc
+++ b/rs_bindings_from_cc/cmdline_test.cc
@@ -212,6 +212,28 @@
                            Pair(HeaderName("d.h"), BazelLabel("//:target2"))));
 }
 
+TEST(CmdlineTest, TargetArgsIntInsteadOfFeaturesArray) {
+  ASSERT_THAT(TestCmdline({"h1"}, R"([{"t": "t1", "f": 123}])"),
+              StatusIs(absl::StatusCode::kInvalidArgument,
+                       AllOf(HasSubstr("--target_args"), HasSubstr(".f"),
+                             HasSubstr("array"))));
+}
+
+TEST(CmdlineTest, TargetArgsEmptyFeature) {
+  ASSERT_THAT(TestCmdline({"h1"}, R"([{"t": "t1", "f": ["", "h2"]}])"),
+              StatusIs(absl::StatusCode::kInvalidArgument,
+                       AllOf(HasSubstr("--target_args"), HasSubstr("`f`"),
+                             HasSubstr("empty string"))));
+}
+
+TEST(CmdlineTest, TargetArgsIntInsteadOfFeature) {
+  ASSERT_THAT(
+      TestCmdline({"h1"}, R"([{"t": "t1", "f": [123, "experimental"]}])"),
+      StatusIs(absl::StatusCode::kInvalidArgument,
+               AllOf(HasSubstr("--target_args"), HasSubstr(".f"),
+                     HasSubstr("string"))));
+}
+
 TEST(CmdlineTest, InstantiationsOutEmpty) {
   constexpr absl::string_view kTargetsAndHeaders = R"([
     {"t": "//:target1", "h": ["a.h", "b.h"]}
diff --git a/rs_bindings_from_cc/generate_bindings_and_metadata.cc b/rs_bindings_from_cc/generate_bindings_and_metadata.cc
index 3a4ca04..2e3da3e 100644
--- a/rs_bindings_from_cc/generate_bindings_and_metadata.cc
+++ b/rs_bindings_from_cc/generate_bindings_and_metadata.cc
@@ -72,7 +72,8 @@
           /* extra_source_code_for_testing= */ "", cmdline.current_target(),
           cmdline.public_headers(), virtual_headers_contents_for_testing,
           cmdline.headers_to_targets(), cmdline.extra_rs_srcs(),
-          clang_args_view, requested_instantiations));
+          clang_args_view, requested_instantiations,
+          cmdline.target_to_features()));
 
   if (!cmdline.instantiations_out().empty()) {
     ir.crate_root_path = "__cc_template_instantiations_rs_api";
diff --git a/rs_bindings_from_cc/ir.cc b/rs_bindings_from_cc/ir.cc
index a2f7342..161089a 100644
--- a/rs_bindings_from_cc/ir.cc
+++ b/rs_bindings_from_cc/ir.cc
@@ -542,11 +542,21 @@
     top_level_ids.push_back(id.value());
   }
 
+  llvm::json::Object features_json;
+  for (const auto& [target, features] : crubit_features) {
+    std::vector<llvm::json::Value> feature_array;
+    for (const std::string& feature : features) {
+      feature_array.push_back(feature);
+    }
+    features_json[target.value()] = std::move(feature_array);
+  }
+
   llvm::json::Object result{
       {"public_headers", public_headers},
       {"current_target", current_target},
       {"items", std::move(json_items)},
       {"top_level_item_ids", std::move(top_level_ids)},
+      {"crubit_features", std::move(features_json)},
   };
   if (!crate_root_path.empty()) {
     result["crate_root_path"] = crate_root_path;
diff --git a/rs_bindings_from_cc/ir.h b/rs_bindings_from_cc/ir.h
index 9a5f0a6..ed4e12d 100644
--- a/rs_bindings_from_cc/ir.h
+++ b/rs_bindings_from_cc/ir.h
@@ -788,6 +788,9 @@
   // TODO(hlopko): Replace empty strings with std::optional<std::string>
   // throughout the codebase
   std::string crate_root_path;
+
+  absl::flat_hash_map<BazelLabel, absl::flat_hash_set<std::string>>
+      crubit_features;
 };
 
 inline std::string IrToJson(const IR& ir) {
diff --git a/rs_bindings_from_cc/ir.rs b/rs_bindings_from_cc/ir.rs
index a6fd468..859b644 100644
--- a/rs_bindings_from_cc/ir.rs
+++ b/rs_bindings_from_cc/ir.rs
@@ -26,14 +26,28 @@
 
 /// Create a testing `IR` instance from given parts. This function does not use
 /// any mock values.
-pub fn make_ir_from_parts(
+pub fn make_ir_from_parts<CrubitFeatures>(
     items: Vec<Item>,
     public_headers: Vec<HeaderName>,
     current_target: BazelLabel,
     top_level_item_ids: Vec<ItemId>,
     crate_root_path: Option<Rc<str>>,
-) -> Result<IR> {
-    make_ir(FlatIR { public_headers, current_target, items, top_level_item_ids, crate_root_path })
+    crubit_features: HashMap<BazelLabel, CrubitFeatures>,
+) -> Result<IR>
+where
+    CrubitFeatures: Into<flagset::FlagSet<CrubitFeature>>,
+{
+    make_ir(FlatIR {
+        public_headers,
+        current_target,
+        items,
+        top_level_item_ids,
+        crate_root_path,
+        crubit_features: crubit_features
+            .into_iter()
+            .map(|(label, features)| (label, CrubitFeaturesIR(features.into())))
+            .collect(),
+    })
 }
 
 fn make_ir(flat_ir: FlatIR) -> Result<IR> {
@@ -683,7 +697,52 @@
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Deserialize)]
+flagset::flags! {
+    pub enum CrubitFeature : u8 {
+        Supported,
+        /// Experimental is never *set* without also setting Supported, but we allow it to be
+        /// *required* without also requiring Supported, so that error messages can be more direct.
+        Experimental,
+    }
+}
+
+impl CrubitFeature {
+    /// The name of this feature.
+    pub fn short_name(&self) -> &'static str {
+        match self {
+            Self::Supported => "supported",
+            Self::Experimental => "experimental",
+        }
+    }
+}
+
+/// A newtype around a flagset of features, so that it can be deserialized from
+/// an array of strings instead of an integer.
+#[derive(Debug, Default, PartialEq, Eq, Clone)]
+struct CrubitFeaturesIR(pub(crate) flagset::FlagSet<CrubitFeature>);
+
+impl<'de> serde::Deserialize<'de> for CrubitFeaturesIR {
+    fn deserialize<D>(deserializer: D) -> Result<CrubitFeaturesIR, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let mut features = flagset::FlagSet::<CrubitFeature>::default();
+        for feature in <Vec<String> as serde::Deserialize<'de>>::deserialize(deserializer)? {
+            features |= match &*feature {
+                "experimental" => CrubitFeature::Experimental,
+                "supported" => CrubitFeature::Supported,
+                other => {
+                    return Err(<D::Error as serde::de::Error>::custom(format!(
+                        "Unexpected Crubit feature: {other}"
+                    )));
+                }
+            };
+        }
+        Ok(CrubitFeaturesIR(features))
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Deserialize)]
 #[serde(rename(deserialize = "IR"))]
 struct FlatIR {
     #[serde(default)]
@@ -695,6 +754,8 @@
     top_level_item_ids: Vec<ItemId>,
     #[serde(default)]
     crate_root_path: Option<Rc<str>>,
+    #[serde(default)]
+    crubit_features: HashMap<BazelLabel, CrubitFeaturesIR>,
 }
 
 /// Struct providing the necessary information about the API of a C++ target to
@@ -793,13 +854,19 @@
         self.flat_ir.items.get(idx).with_context(|| format!("Couldn't find an item at idx {}", idx))
     }
 
-    // Returns whether `target` is the current target.
+    /// Returns whether `target` is the current target.
     pub fn is_current_target(&self, target: &BazelLabel) -> bool {
         // TODO(hlopko): Make this be a pointer comparison, now it's comparing string
         // values.
         *target == *self.current_target()
     }
 
+    /// Returns the Crubit features enabled for the given `target`.
+    #[must_use]
+    pub fn target_crubit_features(&self, target: &BazelLabel) -> flagset::FlagSet<CrubitFeature> {
+        self.flat_ir.crubit_features.get(target).cloned().unwrap_or_default().0
+    }
+
     pub fn current_target(&self) -> &BazelLabel {
         &self.flat_ir.current_target
     }
@@ -896,6 +963,7 @@
             top_level_item_ids: vec![],
             items: vec![],
             crate_root_path: None,
+            crubit_features: Default::default(),
         };
         assert_eq!(ir.flat_ir, expected);
     }
diff --git a/rs_bindings_from_cc/ir_from_cc.cc b/rs_bindings_from_cc/ir_from_cc.cc
index 4fff0ac..2a45a07 100644
--- a/rs_bindings_from_cc/ir_from_cc.cc
+++ b/rs_bindings_from_cc/ir_from_cc.cc
@@ -39,7 +39,9 @@
     absl::flat_hash_map<HeaderName, BazelLabel> headers_to_targets,
     absl::Span<const std::string> extra_rs_srcs,
     absl::Span<const absl::string_view> clang_args,
-    absl::Span<const std::string> extra_instantiations) {
+    absl::Span<const std::string> extra_instantiations,
+    const absl::flat_hash_map<BazelLabel, absl::flat_hash_set<std::string>>&
+        crubit_features) {
   // Caller should verify that the inputs are not empty.
   CHECK(!extra_source_code_for_testing.empty() || !public_headers.empty() ||
         !extra_instantiations.empty());
@@ -115,6 +117,7 @@
     invocation.ir_.top_level_item_ids.push_back(id);
     ++i;
   }
+  invocation.ir_.crubit_features = std::move(crubit_features);
   return invocation.ir_;
 }
 
diff --git a/rs_bindings_from_cc/ir_from_cc.h b/rs_bindings_from_cc/ir_from_cc.h
index 9dc7345..347d9b0 100644
--- a/rs_bindings_from_cc/ir_from_cc.h
+++ b/rs_bindings_from_cc/ir_from_cc.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "absl/container/flat_hash_map.h"
+#include "absl/container/flat_hash_set.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
 #include "absl/types/span.h"
@@ -41,9 +42,10 @@
 //   `virtual_headers_contents_for_testing` are not added automatically.
 // * `clang_args`: additional command line arguments for Clang
 // * `extra_rs_srcs`: A list of paths for additional rust files to include into
-//   the crate. This is done via `#[path="..."] mod <...>; pub use <...>::*;`.
+//    the crate. This is done via `#[path="..."] mod <...>; pub use <...>::*;`.
 // * `extra_instantiations`: names of full C++ class template specializations
-// to instantiate and generate bindings from.
+//   to instantiate and generate bindings from.
+// * `crubit_features`: The set of Crubit features to enable for each target.
 //
 absl::StatusOr<IR> IrFromCc(
     absl::string_view extra_source_code_for_testing,
@@ -54,7 +56,9 @@
     absl::flat_hash_map<HeaderName, BazelLabel> headers_to_targets = {},
     absl::Span<const std::string> extra_rs_srcs = {},
     absl::Span<const absl::string_view> clang_args = {},
-    absl::Span<const std::string> extra_instantiations = {});
+    absl::Span<const std::string> extra_instantiations = {},
+    const absl::flat_hash_map<BazelLabel, absl::flat_hash_set<std::string>>&
+        crubit_features = {});
 
 }  // namespace crubit
 
diff --git a/rs_bindings_from_cc/ir_testing.rs b/rs_bindings_from_cc/ir_testing.rs
index c2cb35b..1cfe5d7 100644
--- a/rs_bindings_from_cc/ir_testing.rs
+++ b/rs_bindings_from_cc/ir_testing.rs
@@ -35,12 +35,14 @@
 /// Create a testing `IR` instance from given items, using mock values for other
 /// fields.
 pub fn make_ir_from_items(items: impl IntoIterator<Item = Item>) -> Result<IR> {
+    let target: ir::BazelLabel = TESTING_TARGET.into();
     make_ir_from_parts(
         items.into_iter().collect_vec(),
         /* public_headers= */ vec![],
-        /* current_target= */ TESTING_TARGET.into(),
+        /* current_target= */ target.clone(),
         /* top_level_item_ids= */ vec![],
         /* crate_root_path= */ None,
+        /* crubit_features= */ [(target, ir::CrubitFeature::Experimental)].into()
     )
 }
 
diff --git a/rs_bindings_from_cc/src_code_gen.rs b/rs_bindings_from_cc/src_code_gen.rs
index 55dca09..ebe975d 100644
--- a/rs_bindings_from_cc/src_code_gen.rs
+++ b/rs_bindings_from_cc/src_code_gen.rs
@@ -191,9 +191,24 @@
         //
         // TODO(b/255784681): Consider including cmdline arguments.
         let target = &ir.current_target().0;
+
+        let crubit_features = {
+            let mut crubit_features: Vec<&str> = ir
+                .target_crubit_features(ir.current_target())
+                .into_iter()
+                .map(|feature| feature.short_name())
+                .collect();
+            crubit_features.sort();
+            if crubit_features.is_empty() {
+                "<none>".to_string()
+            } else {
+                crubit_features.join(", ")
+            }
+        };
         format!(
             "// Automatically @generated Rust bindings for the following C++ target:\n\
-            // {target}\n"
+            // {target}\n\
+            // Features: {crubit_features}\n"
         )
     };
     // TODO(lukasza): Try to remove `#![rustfmt:skip]` - in theory it shouldn't
diff --git a/rs_bindings_from_cc/test/golden/BUILD b/rs_bindings_from_cc/test/golden/BUILD
index 3a80e06..345b00f 100644
--- a/rs_bindings_from_cc/test/golden/BUILD
+++ b/rs_bindings_from_cc/test/golden/BUILD
@@ -44,6 +44,7 @@
 [cc_library(
     name = name + "_cc",
     hdrs = [name + ".h"],
+    aspect_hints = ["//third_party/crubit:experimental"],
     copts = ["-Wno-google3-inline-namespace"],
     deps = [
         ((d + "_cc") if d in TESTS else d)
diff --git a/rs_bindings_from_cc/test/golden/bitfields_rs_api.rs b/rs_bindings_from_cc/test/golden/bitfields_rs_api.rs
index 87dead5..954e92d 100644
--- a/rs_bindings_from_cc/test/golden/bitfields_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/bitfields_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:bitfields_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/bitfields_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/bitfields_rs_api_impl.cc
index 7165dc5..dee8348 100644
--- a/rs_bindings_from_cc/test/golden/bitfields_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/bitfields_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:bitfields_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
index 60a624f..bbebdb2 100644
--- a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:clang_attrs_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api_impl.cc
index b509508..c9a9342 100644
--- a/rs_bindings_from_cc/test/golden/clang_attrs_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/clang_attrs_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:clang_attrs_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/comment_rs_api.rs b/rs_bindings_from_cc/test/golden/comment_rs_api.rs
index 5b08ebd..b6c3002 100644
--- a/rs_bindings_from_cc/test/golden/comment_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/comment_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:comment_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/comment_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/comment_rs_api_impl.cc
index 3b44348..ea6f18a 100644
--- a/rs_bindings_from_cc/test/golden/comment_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/comment_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:comment_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs b/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
index beb2148..4045942 100644
--- a/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/doc_comment_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:doc_comment_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/doc_comment_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/doc_comment_rs_api_impl.cc
index fe80667..d07ec2e 100644
--- a/rs_bindings_from_cc/test/golden/doc_comment_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/doc_comment_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:doc_comment_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/enums_rs_api.rs b/rs_bindings_from_cc/test/golden/enums_rs_api.rs
index fb0f89a..ca12000 100644
--- a/rs_bindings_from_cc/test/golden/enums_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/enums_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:enums_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/enums_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/enums_rs_api_impl.cc
index da5308c..cc3fe57 100644
--- a/rs_bindings_from_cc/test/golden/enums_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/enums_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:enums_cc
+// Features: experimental, supported
 
 #include <memory>
 
diff --git a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
index 0b92b58..0bb4e43 100644
--- a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:escaping_keywords_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api_impl.cc
index 5e5f9da..faae6af 100644
--- a/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/escaping_keywords_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:escaping_keywords_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs b/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs
index 1d9a6d0..20101a1 100644
--- a/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/friend_functions_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:friend_functions_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/friend_functions_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/friend_functions_rs_api_impl.cc
index baee514..e3d1a5a 100644
--- a/rs_bindings_from_cc/test/golden/friend_functions_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/friend_functions_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:friend_functions_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/includes_rs_api.rs b/rs_bindings_from_cc/test/golden/includes_rs_api.rs
index b36d324..9a47ca5 100644
--- a/rs_bindings_from_cc/test/golden/includes_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/includes_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:includes_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/includes_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/includes_rs_api_impl.cc
index 773f407..fce529a 100644
--- a/rs_bindings_from_cc/test/golden/includes_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/includes_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:includes_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs b/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
index da29d0e..d385932 100644
--- a/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/inheritance_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:inheritance_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/inheritance_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/inheritance_rs_api_impl.cc
index 63c6784..807a8f5 100644
--- a/rs_bindings_from_cc/test/golden/inheritance_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/inheritance_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:inheritance_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/item_order_rs_api.rs b/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
index c1bedce..1b65fae 100644
--- a/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/item_order_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:item_order_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/item_order_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/item_order_rs_api_impl.cc
index 06fb8ee..d17bfca 100644
--- a/rs_bindings_from_cc/test/golden/item_order_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/item_order_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:item_order_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs b/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
index 1e4a5f0..c18a296 100644
--- a/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/lifetimes_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:lifetimes_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/lifetimes_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/lifetimes_rs_api_impl.cc
index 892b44f..a9ab319 100644
--- a/rs_bindings_from_cc/test/golden/lifetimes_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/lifetimes_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:lifetimes_cc
+// Features: experimental, supported
 
 #include <memory>
 
diff --git a/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api.rs b/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api.rs
index 2cf3714..a44ac4d 100644
--- a/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:method_qualifiers_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls)]
diff --git a/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api_impl.cc
index a27db28..0dbf4e9 100644
--- a/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/method_qualifiers_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:method_qualifiers_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/namespace_rs_api.rs b/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
index 8490e3e..24fcbc9 100644
--- a/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/namespace_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:namespace_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/namespace_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/namespace_rs_api_impl.cc
index 8ff05e9..0fd038b 100644
--- a/rs_bindings_from_cc/test/golden/namespace_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/namespace_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:namespace_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
index 96f2d80..7475538 100644
--- a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:no_elided_lifetimes_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls)]
diff --git a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api_impl.cc
index 7ca63d9..fdc5480 100644
--- a/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/no_elided_lifetimes_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:no_elided_lifetimes_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/no_unique_address_rs_api.rs b/rs_bindings_from_cc/test/golden/no_unique_address_rs_api.rs
index 1fb6361..09d6ea1 100644
--- a/rs_bindings_from_cc/test/golden/no_unique_address_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/no_unique_address_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:no_unique_address_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/no_unique_address_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/no_unique_address_rs_api_impl.cc
index 3afab36..1ada90f 100644
--- a/rs_bindings_from_cc/test/golden/no_unique_address_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/no_unique_address_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:no_unique_address_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
index a3e07b1..631ba4a 100644
--- a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:nontrivial_type_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api_impl.cc
index b3d7556..8f35418 100644
--- a/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/nontrivial_type_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:nontrivial_type_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/operators_rs_api.rs b/rs_bindings_from_cc/test/golden/operators_rs_api.rs
index 2b3561e..0aa0933 100644
--- a/rs_bindings_from_cc/test/golden/operators_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/operators_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:operators_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/operators_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/operators_rs_api_impl.cc
index 55074ab..0b2cdd9 100644
--- a/rs_bindings_from_cc/test/golden/operators_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/operators_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:operators_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/overloads_rs_api.rs b/rs_bindings_from_cc/test/golden/overloads_rs_api.rs
index b57543d..ac9debe 100644
--- a/rs_bindings_from_cc/test/golden/overloads_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/overloads_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:overloads_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/overloads_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/overloads_rs_api_impl.cc
index 2548a3f..90413ce 100644
--- a/rs_bindings_from_cc/test/golden/overloads_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/overloads_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:overloads_cc
+// Features: experimental, supported
 
 #include <memory>
 
diff --git a/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs b/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
index 36c41c3..96812a3 100644
--- a/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/polymorphic_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:polymorphic_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/polymorphic_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/polymorphic_rs_api_impl.cc
index e3b4a6a..83fc5a4 100644
--- a/rs_bindings_from_cc/test/golden/polymorphic_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/polymorphic_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:polymorphic_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/private_members_rs_api.rs b/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
index 0310832..7807ace 100644
--- a/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/private_members_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:private_members_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/private_members_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/private_members_rs_api_impl.cc
index 8decf98..99c8391 100644
--- a/rs_bindings_from_cc/test/golden/private_members_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/private_members_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:private_members_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/private_method_rs_api.rs b/rs_bindings_from_cc/test/golden/private_method_rs_api.rs
index 943a487..b06101f 100644
--- a/rs_bindings_from_cc/test/golden/private_method_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/private_method_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:private_method_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls)]
diff --git a/rs_bindings_from_cc/test/golden/private_method_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/private_method_rs_api_impl.cc
index 0201bf4..e94439c 100644
--- a/rs_bindings_from_cc/test/golden/private_method_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/private_method_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:private_method_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api.rs b/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api.rs
index d52db59..74a303a 100644
--- a/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:source_location_doc_comments_macro_def_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api_impl.cc
index 9d58a96..a79f03a 100644
--- a/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/source_location_doc_comments_macro_def_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:source_location_doc_comments_macro_def_cc
+// Features: experimental, supported
 
 #include <memory>
 
diff --git a/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api.rs b/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api.rs
index d2aca22..7285529 100644
--- a/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:source_location_doc_comments_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls)]
diff --git a/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api_impl.cc
index d668cc0..60d445c 100644
--- a/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/source_location_doc_comments_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:source_location_doc_comments_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs b/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
index 1b34904..725595d 100644
--- a/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/static_methods_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:static_methods_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/static_methods_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/static_methods_rs_api_impl.cc
index 96f63dd..d1a2cfc 100644
--- a/rs_bindings_from_cc/test/golden/static_methods_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/static_methods_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:static_methods_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/templates_rs_api.rs b/rs_bindings_from_cc/test/golden/templates_rs_api.rs
index 1cbe589..b807471 100644
--- a/rs_bindings_from_cc/test/golden/templates_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/templates_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:templates_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/templates_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/templates_rs_api_impl.cc
index e50fb99..21b7939 100644
--- a/rs_bindings_from_cc/test/golden/templates_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/templates_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:templates_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/templates_source_order_rs_api.rs b/rs_bindings_from_cc/test/golden/templates_source_order_rs_api.rs
index 913332f..df8937c 100644
--- a/rs_bindings_from_cc/test/golden/templates_source_order_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/templates_source_order_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:templates_source_order_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/templates_source_order_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/templates_source_order_rs_api_impl.cc
index 9501da4..506004d 100644
--- a/rs_bindings_from_cc/test/golden/templates_source_order_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/templates_source_order_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:templates_source_order_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs b/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
index 3334fae..d814f8b 100644
--- a/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/trivial_type_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:trivial_type_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/trivial_type_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/trivial_type_rs_api_impl.cc
index caf61c3..f384b17 100644
--- a/rs_bindings_from_cc/test/golden/trivial_type_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/trivial_type_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:trivial_type_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/typedefs_rs_api.rs b/rs_bindings_from_cc/test/golden/typedefs_rs_api.rs
index cfbd0d7..034f943 100644
--- a/rs_bindings_from_cc/test/golden/typedefs_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/typedefs_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:typedefs_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/typedefs_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/typedefs_rs_api_impl.cc
index b8a7ab6..90f56d8 100644
--- a/rs_bindings_from_cc/test/golden/typedefs_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/typedefs_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:typedefs_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/types_rs_api.rs b/rs_bindings_from_cc/test/golden/types_rs_api.rs
index 32d8003..862cb24 100644
--- a/rs_bindings_from_cc/test/golden/types_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/types_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:types_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/types_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/types_rs_api_impl.cc
index 4c64f0e..9df2718 100644
--- a/rs_bindings_from_cc/test/golden/types_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/types_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:types_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/unions_rs_api.rs b/rs_bindings_from_cc/test/golden/unions_rs_api.rs
index 9d87bd1..01cec48 100644
--- a/rs_bindings_from_cc/test/golden/unions_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/unions_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:unions_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/unions_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/unions_rs_api_impl.cc
index 83342a6..81bfb26 100644
--- a/rs_bindings_from_cc/test/golden/unions_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/unions_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:unions_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs b/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
index a2f66d6..6d4870b 100644
--- a/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/unsupported_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:unsupported_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/unsupported_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/unsupported_rs_api_impl.cc
index c1cc0d3..6374ed7 100644
--- a/rs_bindings_from_cc/test/golden/unsupported_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/unsupported_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:unsupported_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
index e9c7f29..a53cd15 100644
--- a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_base_class_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes, negative_impls, type_alias_impl_trait)]
diff --git a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api_impl.cc
index 902f739..42d5acf 100644
--- a/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/user_of_base_class_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_base_class_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
index 50f4b50..f66eff8 100644
--- a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_imported_type_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api_impl.cc
index 8178b21..e25837c 100644
--- a/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/user_of_imported_type_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_imported_type_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>
diff --git a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
index 9f531f8..1a33c57 100644
--- a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
+++ b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api.rs
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_unsupported_cc
+// Features: experimental, supported
 
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]
diff --git a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api_impl.cc b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api_impl.cc
index f11da7c..e214a87 100644
--- a/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api_impl.cc
+++ b/rs_bindings_from_cc/test/golden/user_of_unsupported_rs_api_impl.cc
@@ -4,6 +4,7 @@
 
 // Automatically @generated Rust bindings for the following C++ target:
 // //rs_bindings_from_cc/test/golden:user_of_unsupported_cc
+// Features: experimental, supported
 
 #include <cstddef>
 #include <memory>