FI-X is a Chrome extension developed by mariojankovic. This free tool falls under the Browsers category, specifically in the Add-ons & Tools subcategory. The main purpose of FI-X is to address the issue of X.com not closing when users press the X button. It focuses on enhancing the close button experience after the transition from Twitter to X, where a new close button on the top left-hand corner was introduced but deemed unusable.

FI-X offers users a solution to improve the functionality of the close button within the browser, ensuring a smoother and more user-friendly experience when attempting to close X.com tabs. This extension aims to provide a simple yet effective enhancement for users encountering difficulties with the existing close button.