6 files declare their use of EntityFinderInterface in Feeds 8.3

ConfigEntityReference.php in src/Feeds/Target/ConfigEntityReference.php

EntityReference.php in src/Feeds/Target/EntityReference.php

EntityReferenceTestBase.php in tests/src/Unit/Feeds/Target/EntityReferenceTestBase.php

File.php in src/Feeds/Target/File.php

FileTest.php in tests/src/Unit/Feeds/Target/FileTest.php

FileTestBase.php in tests/src/Kernel/Feeds/Target/FileTestBase.php