Asset preloading is a technique used in web development where certain files (such as images, scripts, or stylesheets) are loaded or fetched in advance before they are actually needed. This is often done to improve the performance of a website or web application.

In simpler terms - when you hover over a link, this tool will start loading the next page. So when you click the link, It will load a lot faster!

To check if your theme already includes it, open any page in Chrome and open Chrome's developer tools. To access Chrome's developer tools, you can right-click anywhere on the page and select 'Inspect'. Alternatively, you can press 'Ctrl + Shift + I' (Windows/Linux) or 'Cmd + Option + I' (Mac) on your keyboard. In the developer tools, navigate to the 'Network' tab. Hover over several links. If you notice additional assets like JavaScripts, stylesheets, or images being loaded in the network tab, it means your theme likely already includes it.