Magento 2 : What template engine is used for email templates?

Question

What template engine is used for Magento2's email templates? I've not been able to get confirmation on this.

Answer 1

As I understand, they still use a custom template "engine" developed by varien inc. which originally developed magento.

You can see how it works in the magento sources: https://github.com/inviqa/magento-community/blob/master/lib/Varien/Filter/Template.php