ansible/changelogs/fragments/variable_names.yml

bugfixes:
  - variables - Added Jinja scalar singletons (``true``, ``false``, ``none``) to invalid Ansible variable name detection.
    Previously, variables with these names could be assigned without error, but could not be resolved.
minor_changes:
  - variables - Removed restriction on usage of most Python keywords as Ansible variable names.
deprecated_features:
  - inventory plugins - Setting invalid Ansible variable names in inventory plugins is deprecated.