6 files declare their use of Merge in Drupal 8

DatabaseLegacyTest.php in core/tests/Drupal/KernelTests/Core/Database/DatabaseLegacyTest.php

DatabaseStorage.php in core/lib/Drupal/Core/KeyValueStore/DatabaseStorage.php

Merge.php in core/lib/Drupal/Core/Database/Driver/sqlite/Merge.php

Merge.php in core/lib/Drupal/Core/Database/Driver/pgsql/Merge.php

Merge.php in core/lib/Drupal/Core/Database/Driver/mysql/Merge.php

MergeTest.php in core/tests/Drupal/KernelTests/Core/Database/MergeTest.php