edlp_d8/sites/all/modules/contrib/taxonomy/synonyms/synonyms.module

<?php

/**
 * @file
 * Provide synonyms feature for content entities.
 */

/**
 * Implements hook_entity_base_field_info().
 */
function synonyms_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  if ($entity_type instanceof \Drupal\Core\Entity\ContentEntityTypeInterface) {
    $fields = [];

    $fields['synonyms'] = \Drupal\Core\Field\BaseFieldDefinition::create('string')
      ->setLabel(t('Entity synonyms'))
      ->setDescription(t('A list of known entity synonyms.'))
      ->setComputed(TRUE)
      ->setClass('\Drupal\synonyms\Plugin\SynonymsFieldItemList');

    return $fields;
  }
}

/**
 * Implements hook_views_data().
 */
function synonyms_views_data() {
  $data = [];

  foreach (\Drupal::entityTypeManager()->getDefinitions() as $entity_type) {
    if ($entity_type instanceof \Drupal\Core\Entity\ContentEntityTypeInterface && $entity_type->getBaseTable() && $entity_type->getKey('id')) {
      $data[$entity_type->getBaseTable()]['synonyms'] = [
        'title' => t('Synonyms of @entity_type', [
          '@entity_type' => $entity_type->getLowercaseLabel(),
        ]),
        'filter' => [
          'id' => 'synonyms_entity',
          'real field' => $entity_type->getKey('id'),
          'entity_type' => $entity_type->id(),
        ],
      ];
    }
  }

  return $data;
}