I want to override Drupal registration form, but i don't want to use `page--user--register.html.twig` because in this case I should rewrite all page structure. We had `user-register.tpl.php` in Drupal 7 but I couldn't find the theme name in Drupal 8. thanks.

Its not duplicate for [this question][1] because he is asking about adding fields and I want to override the user template


  [1]: https://drupal.stackexchange.com/questions/218112