diff --git a/stdlib/distutils/extension.pyi b/stdlib/distutils/extension.pyi
index 655ea1e9e..5639f44a6 100644
--- a/stdlib/distutils/extension.pyi
+++ b/stdlib/distutils/extension.pyi
@@ -1,4 +1,20 @@
 class Extension:
+    name: str
+    sources: list[str]
+    include_dirs: list[str]
+    define_macros: list[tuple[str, str | None]]
+    undef_macros: list[str]
+    library_dirs: list[str]
+    libraries: list[str]
+    runtime_library_dirs: list[str]
+    extra_objects: list[str]
+    extra_compile_args: list[str]
+    extra_link_args: list[str]
+    export_symbols: list[str]
+    swig_opts: list[str]
+    depends: list[str]
+    language: str | None
+    optional: bool | None
     def __init__(
         self,
         name: str,
@@ -13,7 +29,7 @@ class Extension:
         extra_compile_args: list[str] | None = ...,
         extra_link_args: list[str] | None = ...,
         export_symbols: list[str] | None = ...,
-        swig_opts: str | None = ...,  # undocumented
+        swig_opts: list[str] | None = ...,
         depends: list[str] | None = ...,
         language: str | None = ...,
         optional: bool | None = ...,