6 files declare their use of DrupalGatherContentClient in GatherContent 8.5

gathercontent.drush.inc in ./gathercontent.drush.inc

Drush command to cli config import.

GatherContentMigrateSource.php in src/Plugin/migrate/source/GatherContentMigrateSource.php

MappingCreator.php in gathercontent_upload/src/Export/MappingCreator.php

MappingImportForm.php in gathercontent_ui/src/Form/MappingImportForm.php

MappingListBuilder.php in gathercontent_ui/src/MappingListBuilder.php

MockDrupalGatherContentClient.php in tests/modules/gathercontent_test/src/MockDrupalGatherContentClient.php