Thank you very much for sharing this module. I'm interested in trying it for compatibility with Prestashop 8.1. The developer is very skilled; it's definitely worth considering purchasing it.
I request Custom Fields & Extra Tabs 2.2.4 by Prestahero for compatibility with Prestashop 1.8.1. Thank you.
https://prestahero.com/138-custom-fields-on-prestashop-product-page.html