11 files declare their use of MigrateLookupInterface in Drupal 9

BlockPluginId.php in core/modules/block/src/Plugin/migrate/process/BlockPluginId.php

BlockVisibility.php in core/modules/block/src/Plugin/migrate/process/BlockVisibility.php

BlockVisibilityTest.php in core/modules/block/tests/src/Unit/Plugin/migrate/process/BlockVisibilityTest.php

FieldBundle.php in core/modules/field/src/Plugin/migrate/process/d7/FieldBundle.php

FieldFile.php in core/modules/file/src/Plugin/migrate/process/d6/FieldFile.php

FieldFileTest.php in core/modules/file/tests/src/Unit/Plugin/migrate/process/d6/FieldFileTest.php

FilterFormatPermission.php in core/modules/filter/src/Plugin/migrate/process/d6/FilterFormatPermission.php

MenuLinkParent.php in core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php

MenuLinkParentTest.php in core/modules/migrate/tests/src/Unit/process/MenuLinkParentTest.php

MigrationLookup.php in core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php

MigrationLookupTestCase.php in core/modules/migrate/tests/src/Unit/process/MigrationLookupTestCase.php