According to this page of the plugin documentation, it is possible to override or to add a new theme by creating a
wp-content/extension/newsletter
folder. While this seems to work for themes, is there any way to customise the single blocks which are used by the visual builder and are stored in the tnp-composer
folder? A requirement would be to make it update-safe, so the changes remain after the newsletter plugin is updated. Just creating a tnp-composer
folder under extensions/
does not work.