Order Confirmation Emails Layouts, Invoice Layouts etc.. are very commonly modified layouts (by Virtuemart Core Team) to support 3rd party payment method. They are changing almost every single release. And the 3rd party extensions are developed to work with original layouts.
So, we decided to not to touch those layouts. In fact, Virtuemart core layout does it jobs. But, if you would like you make some changes on those layouts (email and invoice). The PHP files you need to modify are located under this folder:
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