10 files declare their use of MigrateMessageInterface in Drupal 9

EntityContentBaseTest.php in core/modules/migrate_drupal/tests/src/Kernel/d6/EntityContentBaseTest.php

EventBase.php in core/modules/migrate/src/Event/EventBase.php

MigrateIdMapInterface.php in core/modules/migrate/src/Plugin/MigrateIdMapInterface.php

MigrateMessageCapture.php in core/modules/migrate_drupal_ui/src/Batch/MigrateMessageCapture.php

MigrateMessageTest.php in core/modules/migrate/tests/src/Kernel/MigrateMessageTest.php

MigratePostRowSaveEvent.php in core/modules/migrate/src/Event/MigratePostRowSaveEvent.php

MigratePreRowSaveEvent.php in core/modules/migrate/src/Event/MigratePreRowSaveEvent.php

MigrateTestBase.php in core/modules/migrate/tests/src/Kernel/MigrateTestBase.php

NullIdMap.php in core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php

Sql.php in core/modules/migrate/src/Plugin/migrate/id_map/Sql.php