6 files declare their use of RowPluginBase in Views (for Drupal 7) 8.3

Entity.php in lib/Views/system/Plugin/views/row/Entity.php

Definition of Views\system\Plugin\views\row\Entity.

RowTest.php in tests/views_test_data/lib/Drupal/views_test_data/Plugin/views/row/RowTest.php

Definition of Drupal\views_test_data\Plugin\views\row\RowTest.

Rss.php in lib/Views/node/Plugin/views/row/Rss.php

Definition of Views\node\Plugin\views\row\Rss.

Rss.php in lib/Views/comment/Plugin/views/row/Rss.php

Definition of Views\comment\Plugin\views\row\Rss.

Rss.php in lib/Views/aggregator/Plugin/views/row/Rss.php

Definition of Views\aggregator\Plugin\views\row\Rss.

View.php in lib/Views/search/Plugin/views/row/View.php

Definition of Views\search\Plugin\views\row\View.