[qualiteam]

The widget that retrieves information for the built-in Specification tab is this one:
\XLite\View\Product\Details\Customer\Attributes

Depending on whether a product has a class, or product-specific attributes, or etc..., this widget is being displayed multiple times with different parameters (see \XLite\View\Product\Details\Customer\Page\APage::g etAttributesWidgets() method).

So, if you want a custom tab that displays a list of particular attributes only, you should create a custom module that:
1. Defines the new tab by decorating \XLite\View\Product\Details\Customer\Page\APage::d efineTabs() method and specifying what "view list" will render the tab contents.
2. Create a widget class that renders the needed attributes like \XLite\View\Product\Details\Customer\Attributes widget does
3. Make this widget appear in the "view list" by adding a @ListChild declaration