What is it?

WooCommerce cart fragments is a script that uses the admin-ajax function to update the contents of the cart on each page. In most cases cart fragments will slow down your website or with a lot of visitors even cause downtime. This is because we can’t cache cart fragment requests and it will also load on pages that don’t have a cart and for visitors who have no items in the cart.

You can identify cart fragment requests when it has the following query string in the url: ?wc-ajax=get_refreshed_fragments

How to disable cart fragments?

There are two methods, disabling with a plugin called Disable Cart Fragments or by adding a piece of code to your functions.php: Read more.