Used CSS is a free Chrome extension developed by iamrkerimov. It falls under the category of Browsers and the subcategory of Add-ons & Tools. This extension offers a convenient solution for users who want to improve their website's PageSpeed scores by downloading only the used CSS after interactions.

With Used CSS, users can ensure that they have performed all the necessary actions on a webpage before clicking on the download button. Once the button is clicked, the extension will automatically download only the CSS that has been used after these interactions. This feature helps to optimize website performance by reducing the amount of unnecessary CSS code that is downloaded.

By eliminating unused CSS, website owners can enhance their website's loading speed and overall performance. Used CSS provides a simple yet effective solution for improving PageSpeed scores and delivering a better user experience.