GitHub CSS Highlighter is a free Chrome add-on developed by Matt King. It falls under the category of Browsers and the subcategory of Add-ons & Tools. The purpose of this program is to add web colors to GitHub code pages in any language.

With GitHub CSS Highlighter, users no longer have to struggle to identify the colors associated with hex codes or new colors added in pull requests. This extension simplifies the process by automatically displaying the web color next to the corresponding code.

To use the GitHub CSS Highlighter, simply add the extension to your Chrome browser and start browsing code files on GitHub. It provides a seamless experience for developers and makes it easier to understand and work with code that involves color representation.

Please note that while this extension currently supports GitHub, the developer has mentioned that support for Bitbucket and GCP will be added soon.

Overall, GitHub CSS Highlighter is a useful tool for developers who frequently work with code on GitHub and want a more visual representation of web colors.