9 files declare their use of ProcessorBase in Purge 8.3

AProcessor.php in tests/modules/purge_processor_test/src/Plugin/Purge/Processor/AProcessor.php

BProcessor.php in tests/modules/purge_processor_test/src/Plugin/Purge/Processor/BProcessor.php

CProcessor.php in tests/modules/purge_processor_test/src/Plugin/Purge/Processor/CProcessor.php

CronProcessor.php in modules/purge_processor_cron/src/Plugin/Purge/Processor/CronProcessor.php

DrushInvalidateProcessor.php in modules/purge_drush/src/Plugin/Purge/Processor/DrushInvalidateProcessor.php

DrushQueueWorkProcessor.php in modules/purge_drush/src/Plugin/Purge/Processor/DrushQueueWorkProcessor.php

LateRuntimeProcessor.php in modules/purge_processor_lateruntime/src/Plugin/Purge/Processor/LateRuntimeProcessor.php

PurgeBlockProcessor.php in modules/purge_ui/src/Plugin/Purge/Processor/PurgeBlockProcessor.php

WithFormProcessor.php in tests/modules/purge_processor_test/src/Plugin/Purge/Processor/WithFormProcessor.php