one note is, that when I tried just to rename the default tabs based on the woocommerce tutorial, I get fatal errors from your theme
I have used the following snippet in my child theme functions.php
/**
* Rename product data tabs
*/
add_filter( ‘woocommerce_product_tabs’, ‘woo_rename_tabs’, 98 );
function woo_rename_tabs( $tabs ) {
$tabs[‘additional_information’][‘title’] = __( ‘Specifications’ ); // Rename the additional information tab
return $tabs;
}