17 files declare their use of MigrationPluginManagerInterface

CredentialForm.php in core/modules/migrate_drupal_ui/src/Form/CredentialForm.php
FieldDiscovery.php in core/modules/migrate_drupal/src/FieldDiscovery.php
FieldDiscoveryTest.php in core/modules/migrate_drupal/tests/src/Unit/FieldDiscoveryTest.php
FieldDiscoveryTestClass.php in core/modules/migrate_drupal/tests/modules/field_discovery_test/src/FieldDiscoveryTestClass.php
FieldDiscoveryTestTrait.php in core/modules/migrate_drupal/tests/src/Traits/FieldDiscoveryTestTrait.php
FieldMigration.php in core/modules/migrate_drupal/src/Plugin/migrate/FieldMigration.php
IncrementalForm.php in core/modules/migrate_drupal_ui/src/Form/IncrementalForm.php
MigrateLookup.php in core/modules/migrate/src/MigrateLookup.php
MigrateLookupTest.php in core/modules/migrate/tests/src/Unit/MigrateLookupTest.php
MigrateStub.php in core/modules/migrate/src/MigrateStub.php
MigrateStubTest.php in core/modules/migrate/tests/src/Unit/MigrateStubTest.php
MigrateUpgradeFormBase.php in core/modules/migrate_drupal_ui/src/Form/MigrateUpgradeFormBase.php
MigrationLookupTest.php in core/modules/migrate/tests/src/Unit/process/MigrationLookupTest.php
MigrationTest.php in core/modules/migrate/tests/src/Unit/MigrationTest.php
Contains \Drupal\Tests\migrate\Unit\MigrationTest.
ReviewForm.php in core/modules/migrate_drupal_ui/src/Form/ReviewForm.php
Sql.php in core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
TestSqlIdMap.php in core/modules/migrate/tests/src/Unit/TestSqlIdMap.php

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