diff --git a/build/gen_stub.php b/build/gen_stub.php
index 6b1556d735196..bbaa251ed695a 100755
--- a/build/gen_stub.php
+++ b/build/gen_stub.php
@@ -2453,6 +2453,8 @@ class ClassInfo {
     public $cond;
     /** @var int|null */
     public $phpVersionIdMinimumCompatibility;
+    /** @var bool */
+    public $isUndocumentable;
 
     /**
      * @param AttributeInfo[] $attributes
@@ -2480,7 +2482,8 @@ public function __construct(
         array $funcInfos,
         array $enumCaseInfos,
         ?string $cond,
-        ?int $minimumPhpVersionIdCompatibility
+        ?int $minimumPhpVersionIdCompatibility,
+        bool $isUndocumentable
     ) {
         $this->name = $name;
         $this->flags = $flags;
@@ -2499,6 +2502,7 @@ public function __construct(
         $this->enumCaseInfos = $enumCaseInfos;
         $this->cond = $cond;
         $this->phpVersionIdMinimumCompatibility = $minimumPhpVersionIdCompatibility;
+        $this->isUndocumentable = $isUndocumentable;
     }
 
     /**
@@ -3088,6 +3092,8 @@ class FileInfo {
     public $generateLegacyArginfoForPhpVersionId;
     /** @var bool */
     public $generateClassEntries = false;
+    /** @var bool */
+    public $isUndocumentable = false;
 
     /**
      * @return iterable<FuncInfo>
@@ -3499,7 +3505,8 @@ function parseClass(
     array $methods,
     array $enumCases,
     ?string $cond,
-    ?int $minimumPhpVersionIdCompatibility
+    ?int $minimumPhpVersionIdCompatibility,
+    bool $isUndocumentable
 ): ClassInfo {
     $flags = $class instanceof Class_ ? $class->flags : 0;
     $comment = $class->getDocComment();
@@ -3521,6 +3528,8 @@ function parseClass(
                 $isStrictProperties = true;
             } else if ($tag->name === 'not-serializable') {
                 $isNotSerializable = true;
+            } else if ($tag->name === 'undocumentable') {
+                $isUndocumentable = true;
             }
         }
     }
@@ -3579,7 +3588,8 @@ function parseClass(
         $methods,
         $enumCases,
         $cond,
-        $minimumPhpVersionIdCompatibility
+        $minimumPhpVersionIdCompatibility,
+        $isUndocumentable
     );
 }
 
@@ -3732,7 +3742,7 @@ function handleStatements(FileInfo $fileInfo, array $stmts, PrettyPrinterAbstrac
             }
 
             $fileInfo->classInfos[] = parseClass(
-                $className, $stmt, $constInfos, $propertyInfos, $methodInfos, $enumCaseInfos, $cond, $fileInfo->generateLegacyArginfoForPhpVersionId
+                $className, $stmt, $constInfos, $propertyInfos, $methodInfos, $enumCaseInfos, $cond, $fileInfo->generateLegacyArginfoForPhpVersionId, $fileInfo->isUndocumentable
             );
             continue;
         }
@@ -3783,6 +3793,8 @@ protected function pName_FullyQualified(Name\FullyQualified $node) {
             } else if ($tag->name === 'generate-class-entries') {
                 $fileInfo->generateClassEntries = true;
                 $fileInfo->declarationPrefix = $tag->value ? $tag->value . " " : "";
+            } else if ($tag->name === 'undocumentable') {
+                $fileInfo->isUndocumentable = true;
             }
         }
     }
@@ -4219,12 +4231,14 @@ function generateClassSynopses(array $classMap, iterable $allConstInfos): array
 }
 
 /**
- * @param ClassInfo[] $classMap
+ * @param array<string, ClassInfo> $classMap
  * $param iterable<ConstInfo> $allConstInfos
  * @return array<string, string>
  */
-function replaceClassSynopses(string $targetDirectory, array $classMap, iterable $allConstInfos): array
+function replaceClassSynopses(string $targetDirectory, array $classMap, iterable $allConstInfos, bool $isVerify): array
 {
+    $existingClassSynopses = [];
+
     $classSynopses = [];
 
     $it = new RecursiveIteratorIterator(
@@ -4281,6 +4295,9 @@ function replaceClassSynopses(string $targetDirectory, array $classMap, iterable
             if (!isset($classMap[$className])) {
                 continue;
             }
+
+            $existingClassSynopses[$className] = $className;
+
             $classInfo = $classMap[$className];
 
             $newClassSynopsis = $classInfo->getClassSynopsisElement($doc, $classMap, $allConstInfos);
@@ -4320,6 +4337,16 @@ function replaceClassSynopses(string $targetDirectory, array $classMap, iterable
         }
     }
 
+    if ($isVerify) {
+        $missingClassSynopses = array_diff_key($classMap, $existingClassSynopses);
+        foreach ($missingClassSynopses as $className => $info) {
+            /** @var ClassInfo $info */
+            if (!$info->isUndocumentable) {
+                echo "Warning: Missing class synopsis page for $className\n";
+            }
+        }
+    }
+
     return $classSynopses;
 }
 
@@ -4791,7 +4818,7 @@ function(?ArgInfo $aliasArg, ?ArgInfo $aliasedArg) use ($aliasFunc, $aliasedFunc
 }
 
 if ($replaceClassSynopses) {
-    $classSynopses = replaceClassSynopses($targetSynopses, $classMap, $context->allConstInfos);
+    $classSynopses = replaceClassSynopses($targetSynopses, $classMap, $context->allConstInfos, $verify);
 
     foreach ($classSynopses as $filename => $content) {
         if (file_put_contents($filename, $content)) {
diff --git a/ext/pdo_pgsql/pgsql_driver.stub.php b/ext/pdo_pgsql/pgsql_driver.stub.php
index 6daa55c7b873a..4206dbea636b9 100644
--- a/ext/pdo_pgsql/pgsql_driver.stub.php
+++ b/ext/pdo_pgsql/pgsql_driver.stub.php
@@ -2,7 +2,10 @@
 
 /** @generate-function-entries */
 
-// These are extension methods for PDO. This is not a real class.
+/**
+ * These are extension methods for PDO. This is not a real class.
+ * @undocumentable
+ */
 class PDO_PGSql_Ext {
     /** @tentative-return-type */
     public function pgsqlCopyFromArray(string $tableName, array $rows, string $separator = "\t", string $nullAs = "\\\\N", ?string $fields = null): bool {}
diff --git a/ext/pdo_pgsql/pgsql_driver_arginfo.h b/ext/pdo_pgsql/pgsql_driver_arginfo.h
index a3ec5196fad2c..3f84d4d8e5b9d 100644
--- a/ext/pdo_pgsql/pgsql_driver_arginfo.h
+++ b/ext/pdo_pgsql/pgsql_driver_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 5dfd421cf9ba9eb043c4b4f3c9b9c09c81cc3ccb */
+ * Stub hash: b30fa6327876dc1090ee5397253c935e4566a8fe */
 
 ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_TYPE_INFO_EX(arginfo_class_PDO_PGSql_Ext_pgsqlCopyFromArray, 0, 2, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, tableName, IS_STRING, 0)
diff --git a/ext/pdo_sqlite/sqlite_driver.stub.php b/ext/pdo_sqlite/sqlite_driver.stub.php
index 58fb41c9b950e..add395f2b99a5 100644
--- a/ext/pdo_sqlite/sqlite_driver.stub.php
+++ b/ext/pdo_sqlite/sqlite_driver.stub.php
@@ -2,7 +2,10 @@
 
 /** @generate-function-entries */
 
-// These are extension methods for PDO. This is not a real class.
+/**
+ * These are extension methods for PDO. This is not a real class.
+ * @undocumentable
+ */
 class PDO_SQLite_Ext {
     /** @tentative-return-type */
     public function sqliteCreateFunction(string $name, callable $callback, int $numArgs = -1, int $flags = 0): bool {}
diff --git a/ext/pdo_sqlite/sqlite_driver_arginfo.h b/ext/pdo_sqlite/sqlite_driver_arginfo.h
index 2b9b1aea1e0ba..5ba745e55cf3e 100644
--- a/ext/pdo_sqlite/sqlite_driver_arginfo.h
+++ b/ext/pdo_sqlite/sqlite_driver_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 8cc3c173f5a442ab80f240a568489b023aabd7ef */
+ * Stub hash: dc901bd60d17c1a2cdb40a118e2c6cd6eb0396e3 */
 
 ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_TYPE_INFO_EX(arginfo_class_PDO_SQLite_Ext_sqliteCreateFunction, 0, 2, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, name, IS_STRING, 0)
diff --git a/ext/standard/basic_functions.stub.php b/ext/standard/basic_functions.stub.php
index f55e4e5b9d291..7e6f9d8afbec3 100755
--- a/ext/standard/basic_functions.stub.php
+++ b/ext/standard/basic_functions.stub.php
@@ -740,6 +740,7 @@
 const LOG_PERROR = UNKNOWN;
 #endif
 
+/** @undocumentable */
 #[AllowDynamicProperties]
 final class __PHP_Incomplete_Class
 {
diff --git a/ext/standard/basic_functions_arginfo.h b/ext/standard/basic_functions_arginfo.h
index 51879da2059ca..e76e056f3e81e 100644
--- a/ext/standard/basic_functions_arginfo.h
+++ b/ext/standard/basic_functions_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 9c86ed1487132d15715ddbfcb5abd6ac52d629eb */
+ * Stub hash: 9e0016895111851aa2c635e1380a18cd7963e58e */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_set_time_limit, 0, 1, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, seconds, IS_LONG, 0)
diff --git a/ext/zend_test/fiber.stub.php b/ext/zend_test/fiber.stub.php
index 4cfe97137d86e..0f6ccf898e29d 100644
--- a/ext/zend_test/fiber.stub.php
+++ b/ext/zend_test/fiber.stub.php
@@ -1,6 +1,9 @@
 <?php
 
-/** @generate-class-entries static */
+/**
+ * @generate-class-entries static
+ * @undocumentable
+ */
 
 final class _ZendTestFiber
 {
diff --git a/ext/zend_test/fiber_arginfo.h b/ext/zend_test/fiber_arginfo.h
index 8c9864ed022f4..a93a15fc3512e 100644
--- a/ext/zend_test/fiber_arginfo.h
+++ b/ext/zend_test/fiber_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 72732355038392236e17ce928354667302c4c6bf */
+ * Stub hash: 8cd7626122b050585503ccebe370a61781ff83f2 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class__ZendTestFiber___construct, 0, 0, 1)
 	ZEND_ARG_TYPE_INFO(0, callback, IS_CALLABLE, 0)
diff --git a/ext/zend_test/test.stub.php b/ext/zend_test/test.stub.php
index 1f60a047f0d29..49efae473dd4a 100644
--- a/ext/zend_test/test.stub.php
+++ b/ext/zend_test/test.stub.php
@@ -3,6 +3,7 @@
 /**
  * @generate-class-entries static
  * @generate-legacy-arginfo 80000
+ * @undocumentable
  */
 namespace {
     /**
diff --git a/ext/zend_test/test_arginfo.h b/ext/zend_test/test_arginfo.h
index 52c784b61e28f..0451daab66e3f 100644
--- a/ext/zend_test/test_arginfo.h
+++ b/ext/zend_test/test_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 42a9cfb3fb78beb59d251712e9dab24364bf1c1c */
+ * Stub hash: 05927aba1708d8718cb59dcadc7b4067323956d2 */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_zend_test_array_return, 0, 0, IS_ARRAY, 0)
 ZEND_END_ARG_INFO()