The translation migrations no longer require that the experimental Migrate Drupal Multilingual module (migrate_drupal_multilingual) is installed on the Drupal site. This covers any type of migration for translations, include those based on the i18n module, node translations and entity translations. All the Multilingual migrations are tagged with a 'Multilingual' migration_tag.
Before
Any migration with the 'Multilingual' tag was only available when the experimental Migrate Drupal Multilingual module was enabled.
After
The multilingual migrations are available without the need to enable the experimental Migrate Drupal Multilingual. Since the whole purpose of the module was to keep multilingual migrations experimental, this also means that multilingual migrations are now stable.
This module will be removed in Drupal 10: #2966859: Remove Migrate Drupal Multilingual module in Drupal 10