Specify that some builds may break due to improper configuration

changelog.d/2894.breaking.rst

@@ -3,8 +3,9 @@ that some Python files (or general folders) might be automatically detected and
 included.
 
 Projects that currently don't specify both ``packages`` and ``py_modules`` in their
-configuration and have extra Python files and folders (not meant for distribution),
-might see these files being included in the wheel archive.
+configuration and contain extra folders or Python files (not meant for distribution),
+might see these files being included in the wheel archive or even experience
+the build to fail.
 
-You can check details about the automatic discovery behaviour (and
-how to configure a different one) in :doc:`/userguide/package_discovery`.
+You can check details about the automatic discovery (and how to configure a
+different behaviour) in :doc:`/userguide/package_discovery`.