This forces customers to go to the solution's page and decide on a mixture, as an alternative to only adding the default one to your cart. Notice that products without any mix will nevertheless have an "Add to cart" button while in the classification web site. Take a look at https://addons.prestashop.com/it/seo-indicizzazione-naturale/30904-tag-hreflang-automatici-e-tag-canonici-seo.html