Dawn tools break site - Can't add fields to contents types

When Dawn tools module is enabled, trying to add a field to a content type creates this error:
Fatal error: Cannot declare class Drupal\field_example\Plugin\Field\FieldType\RgbItem, because the name is already in use in /app/modules/contrib/dawn_tools/src/Plugin/Field/FieldType/RgbItem.php on line 0 Call Stack: 0.0015 390096 1.... (I can post the full error if you can't reproduce)

The error goes away when dawn tools is uninstalled.