11 files declare their use of PageVariantInterface in Page Manager 8

Page.php in src/Entity/Page.php

Contains \Drupal\page_manager\Entity\Page.

PageEditWizard.php in page_manager_ui/src/Wizard/PageEditWizard.php

Contains \Drupal\page_manager_ui\Wizard\PageEditWizard.

PageGeneralForm.php in page_manager_ui/src/Form/PageGeneralForm.php

Contains \Drupal\page_manager_ui\Form\PageGeneralForm.

PageManagerController.php in page_manager_ui/src/Controller/PageManagerController.php

Contains \Drupal\page_manager_ui\Controller\PageManagerController.

PageManagerRoutesTest.php in tests/src/Unit/PageManagerRoutesTest.php

Contains \Drupal\Tests\page_manager\Unit\PageManagerRoutesTest.

PageTest.php in tests/src/Unit/PageTest.php

Contains \Drupal\Tests\page_manager\Unit\PageTest.

PageVariant.php in src/Entity/PageVariant.php

Contains Drupal\page_manager\Entity\PageVariant.

VariantPluginAddBlockForm.php in page_manager_ui/src/Form/VariantPluginAddBlockForm.php

Contains \Drupal\page_manager_ui\Form\VariantPluginAddBlockForm.

VariantPluginConfigureBlockFormBase.php in page_manager_ui/src/Form/VariantPluginConfigureBlockFormBase.php

Contains \Drupal\page_manager_ui\Form\VariantPluginConfigureBlockFormBase.

VariantPluginDeleteBlockForm.php in page_manager_ui/src/Form/VariantPluginDeleteBlockForm.php

Contains \Drupal\page_manager_ui\Form\VariantPluginDeleteBlockForm.

VariantRouteFilterTest.php in tests/src/Unit/VariantRouteFilterTest.php

Contains \Drupal\Tests\page_manager\Unit\VariantRouteFilterTest.