In the Variation Table for WooCommerce, including the quick cart where users can add to cart, this setting controls the hover text color of the add to cart button, allowing you to customize it to match your site’s design and branding.

Here is the frontend show for the quick cart carousel in the WooCommerce shop page. After hovering over the add to cart button, the text color will be changed to what you want.

Here is the frontend show for the variation table for the WooCommerce single product page. After hovering over the add to cart button, the text color will be changed to what you want.