diff --git a/CHANGE_LOG b/CHANGE_LOG
index fe086326..e1f3e56f 100644
--- a/CHANGE_LOG
+++ b/CHANGE_LOG
@@ -1,6 +1,6 @@
 2021-XX-XX   2.1.1:
 -------------------
-  * add type hinting (see PEP 484, 561) using .pyi files
+  * add type hinting (see PEP 484, 561) using stub (`.pyi`) files
   * add tests
 
 
diff --git a/setup.py b/setup.py
index a26d9c37..0f213a9d 100644
--- a/setup.py
+++ b/setup.py
@@ -39,7 +39,9 @@
     ],
     description = "efficient arrays of booleans -- C extension",
     packages = ["bitarray"],
-    package_data = {"bitarray": ["*.h", "*.pickle", "py.typed", "*.pyi"]},
+    package_data = {"bitarray": ["*.h", "*.pickle",
+                                 "py.typed",  # see PEP 561
+                                 "*.pyi"]},
     ext_modules = [Extension(name = "bitarray._bitarray",
                              sources = ["bitarray/_bitarray.c"]),
                    Extension(name = "bitarray._util",