6 files declare their use of CacheCollector in Zircon Profile 8

AliasWhitelist.php in core/lib/Drupal/Core/Path/AliasWhitelist.php

Contains \Drupal\Core\Path\AliasWhitelist.

CacheCollectorHelper.php in core/tests/Drupal/Tests/Core/Cache/CacheCollectorHelper.php

Contains \Drupal\Tests\Core\Cache\CacheCollectorHelper.

LibraryDiscoveryCollector.php in core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php

Contains \Drupal\Core\Asset\LibraryDiscoveryCollector.

LocaleLookup.php in core/modules/locale/src/LocaleLookup.php

Contains \Drupal\locale\LocaleLookup.

MenuActiveTrail.php in core/lib/Drupal/Core/Menu/MenuActiveTrail.php

Contains \Drupal\Core\Menu\MenuActiveTrail.

ThemeRegistry.php in core/lib/Drupal/Core/Utility/ThemeRegistry.php

Contains \Drupal\Core\Utility\ThemeRegistry.