8 files declare their use of ModuleInstallerInterface in Zircon Profile 8

ConfigImporter.php in core/lib/Drupal/Core/Config/ConfigImporter.php

Contains \Drupal\Core\Config\ConfigImporter.

ConfigSingleImportForm.php in core/modules/config/src/Form/ConfigSingleImportForm.php

Contains \Drupal\config\Form\ConfigSingleImportForm.

ConfigSync.php in core/modules/config/src/Form/ConfigSync.php

Contains \Drupal\config\Form\ConfigSync.

ModulesListConfirmForm.php in core/modules/system/src/Form/ModulesListConfirmForm.php

Contains \Drupal\system\Form\ModulesListConfirmForm.

ModulesListForm.php in core/modules/system/src/Form/ModulesListForm.php

Contains \Drupal\system\Form\ModulesListForm.

ModulesUninstallConfirmForm.php in core/modules/system/src/Form/ModulesUninstallConfirmForm.php

Contains \Drupal\system\Form\ModulesUninstallConfirmForm.

ModulesUninstallForm.php in core/modules/system/src/Form/ModulesUninstallForm.php

Contains \Drupal\system\Form\ModulesUninstallForm.

SiteConfigureForm.php in core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php

Contains \Drupal\Core\Installer\Form\SiteConfigureForm.