Issue #27147: Mention PEP 420 in the importlib docs.

Doc/library/importlib.rst

@@ -52,6 +52,9 @@ generically as an :term:`importer`) to participate in the import process.
     :pep:`366`
         Main module explicit relative imports
 
+    :pep:`420`
+        Implicit namespace packages
+
     :pep:`451`
         A ModuleSpec Type for the Import System
 

Misc/NEWS

@@ -106,6 +106,8 @@ Core and Builtins
 
 - Issue #25709: Fixed problem with in-place string concatenation and utf-8 cache.
 
+- Issue #27147: Mention PEP 420 in the importlib docs.
+
 - Issue #24097: Fixed crash in object.__reduce__() if slot name is freed inside
   __getattr__.