Helper Font v4 is a Chrome browser add-on designed to assist web developers in debugging typography on web pages. This free tool simplifies the process of checking which typography classes are applied to text blocks by adding a specific class to the body of any webpage. Users can effortlessly identify if the correct classes such as title-m, label-m, and text-m are in use throughout the interface. The tool enhances the workflow by providing visual cues directly on the page.

The functionality of Helper Font is straightforward; upon activation, it appends the 'helper-font' class to the body tag of the webpage. This allows developers to utilize CSS to highlight the typography classes employed in their projects. Each class is visually distinguished with a colored border and labeled with its respective name, making it easy to review and ensure proper typographic implementation.