12 files declare their use of Theme in Express 8

AlterManager.php in themes/contrib/bootstrap/src/Plugin/AlterManager.php

Contains \Drupal\bootstrap\Plugin\AlterManager.

bootstrap.drush.inc in themes/contrib/bootstrap/bootstrap.drush.inc

Drupal Bootstrap Drush commands.

FormManager.php in themes/contrib/bootstrap/src/Plugin/FormManager.php

Contains \Drupal\bootstrap\Plugin\FormManager.

PluginManager.php in themes/contrib/bootstrap/src/Plugin/PluginManager.php

Contains \Drupal\bootstrap\Plugin\PluginManager.

PreprocessManager.php in themes/contrib/bootstrap/src/Plugin/PreprocessManager.php

Contains \Drupal\bootstrap\Plugin\PreprocessManager.

PrerenderManager.php in themes/contrib/bootstrap/src/Plugin/PrerenderManager.php

Contains \Drupal\bootstrap\Plugin\PrerenderManager.

ProcessManager.php in themes/contrib/bootstrap/src/Plugin/ProcessManager.php

Contains \Drupal\bootstrap\Plugin\ProcessManager.

ProviderManager.php in themes/contrib/bootstrap/src/Plugin/ProviderManager.php

Contains \Drupal\bootstrap\Plugin\ProviderManager.

SettingManager.php in themes/contrib/bootstrap/src/Plugin/SettingManager.php

Contains \Drupal\bootstrap\Plugin\SettingManager.

UpdateBase.php in themes/contrib/bootstrap/src/Plugin/Update/UpdateBase.php

Contains \Drupal\bootstrap\Plugin\Update\UpdateBase.

UpdateInterface.php in themes/contrib/bootstrap/src/Plugin/Update/UpdateInterface.php

Contains \Drupal\bootstrap\Plugin\Update\UpdateInterface.

UpdateManager.php in themes/contrib/bootstrap/src/Plugin/UpdateManager.php

Contains \Drupal\bootstrap\Plugin\UpdateManager.