9 files declare their use of SqlBase

DrupalSqlBase.php in core/modules/migrate_drupal/src/Plugin/migrate/source/DrupalSqlBase.php
HighWaterTest.php in core/modules/migrate/tests/modules/migrate_high_water_test/src/Plugin/migrate/source/HighWaterTest.php
MigrateMissingDatabaseSource.php in core/modules/migrate/tests/modules/migrate_missing_database_test/src/Plugin/migrate/source/MigrateMissingDatabaseSource.php
MigrationPluginListTest.php in core/modules/migrate/tests/src/Kernel/Plugin/MigrationPluginListTest.php
QueryBatchTest.php in core/modules/migrate/tests/modules/migrate_query_batch_test/src/Plugin/migrate/source/QueryBatchTest.php
SqlBaseTest.php in core/modules/migrate/tests/src/Unit/SqlBaseTest.php
SqlBaseTest.php in core/modules/migrate/tests/src/Kernel/SqlBaseTest.php
SqlCountCache.php in core/modules/migrate/tests/modules/migrate_sql_count_cache_test/src/Plugin/migrate/source/SqlCountCache.php
TrackChangesTest.php in core/modules/migrate/tests/modules/migrate_track_changes_test/src/Plugin/migrate/source/TrackChangesTest.php

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