Provides an Administrative UI and Developers API for managing the used mail backend/plugin. The module is ready to be used in Drupal 8, there are no known issues. Allows to use different backends for formatting and sending e-mails by default, per module and per mail key. Additionally, a theme can be configured that is used for sent mails. In Drupal 7, that must be enabled for each template, in Drupal 8, it works reliably for any template being rendered while building and sending e-mails. Administrative UI