diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -1899,6 +1899,8 @@
 #include <__algorithm/upper_bound.h>
 
 // standard-mandated includes
+
+// [algorithm.syn]
 #include <initializer_list>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/bitset b/libcxx/include/bitset
--- a/libcxx/include/bitset
+++ b/libcxx/include/bitset
@@ -125,6 +125,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [bitset.syn]
 #include <iosfwd>
 #include <string>
 
diff --git a/libcxx/include/chrono b/libcxx/include/chrono
--- a/libcxx/include/chrono
+++ b/libcxx/include/chrono
@@ -694,6 +694,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [time.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_LOCALIZATION) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT) && _LIBCPP_STD_VER > 17
diff --git a/libcxx/include/cinttypes b/libcxx/include/cinttypes
--- a/libcxx/include/cinttypes
+++ b/libcxx/include/cinttypes
@@ -236,6 +236,10 @@
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+
+// standard-mandated includes
+
+// [cinttypes.syn]
 #include <cstdint>
 
 #include <inttypes.h>
diff --git a/libcxx/include/coroutine b/libcxx/include/coroutine
--- a/libcxx/include/coroutine
+++ b/libcxx/include/coroutine
@@ -47,6 +47,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [coroutine.syn]
 #include <compare>
 
 #ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
diff --git a/libcxx/include/filesystem b/libcxx/include/filesystem
--- a/libcxx/include/filesystem
+++ b/libcxx/include/filesystem
@@ -449,6 +449,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [fs.filesystem.syn]
 #include <compare>
 
 #if defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
diff --git a/libcxx/include/ios b/libcxx/include/ios
--- a/libcxx/include/ios
+++ b/libcxx/include/ios
@@ -224,6 +224,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [ios.syn]
 #include <iosfwd>
 
 #if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
diff --git a/libcxx/include/iostream b/libcxx/include/iostream
--- a/libcxx/include/iostream
+++ b/libcxx/include/iostream
@@ -38,6 +38,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [iostream.syn]
 #include <ios>
 #include <istream>
 #include <ostream>
diff --git a/libcxx/include/iterator b/libcxx/include/iterator
--- a/libcxx/include/iterator
+++ b/libcxx/include/iterator
@@ -717,13 +717,17 @@
 #include <__iterator/wrap_iter.h>
 #include <__memory/addressof.h>
 #include <__memory/pointer_traits.h>
-#include <compare>
-#include <concepts> // Mandated by the Standard.
 #include <cstddef>
 #include <initializer_list>
 #include <type_traits>
 #include <version>
 
+// standard-mandated includes
+
+// [iterator.synopsis]
+#include <compare>
+#include <concepts>
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
diff --git a/libcxx/include/memory b/libcxx/include/memory
--- a/libcxx/include/memory
+++ b/libcxx/include/memory
@@ -886,6 +886,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [memory.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/optional b/libcxx/include/optional
--- a/libcxx/include/optional
+++ b/libcxx/include/optional
@@ -178,6 +178,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [optional.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/queue b/libcxx/include/queue
--- a/libcxx/include/queue
+++ b/libcxx/include/queue
@@ -232,6 +232,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [queue.syn]
 #include <compare>
 #include <initializer_list>
 
diff --git a/libcxx/include/random b/libcxx/include/random
--- a/libcxx/include/random
+++ b/libcxx/include/random
@@ -1719,6 +1719,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [rand.synopsis]
 #include <initializer_list>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/stack b/libcxx/include/stack
--- a/libcxx/include/stack
+++ b/libcxx/include/stack
@@ -108,6 +108,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [stack.syn]
 #include <compare>
 #include <initializer_list>
 
diff --git a/libcxx/include/system_error b/libcxx/include/system_error
--- a/libcxx/include/system_error
+++ b/libcxx/include/system_error
@@ -156,6 +156,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [system.error.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/thread b/libcxx/include/thread
--- a/libcxx/include/thread
+++ b/libcxx/include/thread
@@ -100,6 +100,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [thread.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/tuple b/libcxx/include/tuple
--- a/libcxx/include/tuple
+++ b/libcxx/include/tuple
@@ -221,6 +221,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [tuple.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/valarray b/libcxx/include/valarray
--- a/libcxx/include/valarray
+++ b/libcxx/include/valarray
@@ -361,6 +361,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [valarray.syn]
 #include <initializer_list>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/variant b/libcxx/include/variant
--- a/libcxx/include/variant
+++ b/libcxx/include/variant
@@ -228,6 +228,8 @@
 #include <version>
 
 // standard-mandated includes
+
+// [variant.syn]
 #include <compare>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)