/** @var \Drupal\Core\Field\BaseFieldDefinition[] $field_definitions */
$field_definitions = $this->container->get('entity_field.manager')
->getBaseFieldDefinitions('media');
/** @var \Drupal\Core\Field\BaseFieldDefinition[] $field_definitions */
$field_definitions = $this->container->get('entity_field.manager')
->getBaseFieldDefinitions('media');