Ace Script is a Firefox extension designed for web development enthusiasts, allowing users to modify the appearance and behavior of web pages through userscripts. It supports scripts compatible with Greasemonkey and Tampermonkey, enabling users to enhance their browsing experience by integrating features from Ace Stream software. Users can either write their own scripts or utilize existing ones available from various sources, ensuring a personalized web interaction.

The extension prioritizes user control, as it does not contain ads or automatically modify web pages. Any changes made to sites are solely based on the scripts installed by the user, emphasizing the importance of using trusted scripts. Users are encouraged to monitor the performance of their scripts and remove any that do not function correctly, providing a safe and customizable web experience.