10 files declare their use of Page in Page Manager 8

FrontPageTest.php in src/Tests/FrontPageTest.php

PageConfigSchemaTest.php in src/Tests/PageConfigSchemaTest.php

Contains \Drupal\page_manager\Tests\PageConfigSchemaTest.

PageManagerAdminTest.php in page_manager_ui/src/Tests/PageManagerAdminTest.php

Contains \Drupal\page_manager_ui\Tests\PageManagerAdminTest.

PageManagerRoutingTest.php in tests/src/Kernel/PageManagerRoutingTest.php

PageNodeAccessTest.php in src/Tests/PageNodeAccessTest.php

Contains \Drupal\page_manager\Tests\PageNodeAccessTest.

PageParametersTest.php in page_manager_ui/src/Tests/PageParametersTest.php

Contains \Drupal\page_manager_ui\Tests\PageParametersTest.php.

PagePlaceholderTest.php in src/Tests/PagePlaceholderTest.php

Contains \Drupal\page_manager\Tests\PageNodeSelectionTest.

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

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

PageVariantPageEntityTest.php in tests/src/Kernel/PageVariantPageEntityTest.php

Contains \Drupal\Tests\page_manager\Kernel\PageVariantPageEntityTest.

SerializationTest.php in tests/src/Kernel/SerializationTest.php

Contains \Drupal\Tests\page_manager\Kernel\SerializationTest.