Document feature flag
@@ -36,3 +36,5 @@ e.g. python-reno release notes manager is known to do that
``USE_TESTING_BUILD_IMAGE``: :featureflags:`USE_TESTING_BUILD_IMAGE`
``EXTERNAL_VERSION_BUILD``: :featureflags:`EXTERNAL_VERSION_BUILD`
+
+``LIST_PACKAGES_INSTALLED_ENV``: :featureflags:`LIST_PACKAGES_INSTALLED_ENV`
