8 files declare their use of PageVariantInterface in Page Manager 8.4

Page.php in src/Entity/Page.php

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

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

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

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

PageVariant.php in src/Entity/PageVariant.php

page_manager.post_update.php in ./page_manager.post_update.php

Post update functions for page_manager module.

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