GitHub Rulers is a free Chrome extension developed by tomas.hubelbauer. It falls under the category of Browsers and specifically, Add-ons & Tools. This extension enhances the GitHub code editor by adding vertical lines that indicate the 0, 80, and 120 character stops.

With GitHub Rulers, users can easily visualize these character stops while editing code on GitHub. This can be particularly helpful for adhering to coding style guidelines or for ensuring consistent code formatting. The vertical lines serve as a visual reference, making it easier to identify when lines of code exceed certain character limits.

The extension seamlessly integrates into the GitHub web editor, providing a simple and unobtrusive way to enhance the editing experience. By displaying the 0, 80, and 120 character stops, GitHub Rulers assists developers in writing clean and readable code directly within the GitHub environment.