8 files declare their use of EntityConfigBase in Drupal 9

DestinationCategoryTest.php in core/modules/migrate_drupal/tests/src/Kernel/Plugin/migrate/DestinationCategoryTest.php

EntityBlock.php in core/modules/block/src/Plugin/migrate/destination/EntityBlock.php

EntityCommentType.php in core/modules/comment/src/Plugin/migrate/destination/EntityCommentType.php

EntityDateFormat.php in core/modules/system/src/Plugin/migrate/destination/EntityDateFormat.php

EntityImageStyle.php in core/modules/image/src/Plugin/migrate/destination/EntityImageStyle.php

EntityNodeType.php in core/modules/node/src/Plugin/migrate/destination/EntityNodeType.php

EntitySearchPage.php in core/modules/search/src/Plugin/migrate/destination/EntitySearchPage.php

EntityShortcutSet.php in core/modules/shortcut/src/Plugin/migrate/destination/EntityShortcutSet.php