With the product-specific custom field "Custom tab – Title" you can name the "Custom tab" on product pages individually.
If you leave this custom field empty, the snippet twt.detail.tabCustom.title is used instead.
You can find the "Custom tab – Title" custom field in the respective product:
Tab "Specifications" ⇒ Block "Custom fields" ⇒ Tab (Set) "Products (ThemeWare® ... Pro)"
Type: Text
Technical name: twt_{theme}_{edition}_custom_field__product__custom_tab_title
You can find more information about the "Custom tab" extension here: