6 files declare their use of ConfigEntityType

ConfigEntityStorageTest.php in core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityStorageTest.php
ConfigEntityTypeTest.php in core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityTypeTest.php
EntityResource.php in core/modules/rest/src/Plugin/rest/resource/EntityResource.php
EntityViewsDataTest.php in core/modules/views/tests/src/Unit/EntityViewsDataTest.php
Contains \Drupal\Tests\views\Unit\EntityViewsDataTest.
rest.install in core/modules/rest/rest.install
Install, update and uninstall functions for the rest module.
RESTTestBase.php in core/modules/rest/src/Tests/RESTTestBase.php

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.