WhatColor is a free Chrome extension developed by cmilhench. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This extension provides a convenient way to identify colors on web pages, making it a valuable tool for web developers and designers.

The main feature of WhatColor is the ability to parse all CSS stylesheet files linked to the current page and create a sidebar that lists all the colors referenced within these stylesheets. This allows users to quickly and easily identify the colors used in a website's design without having to manually inspect the code.

It is important to note that WhatColor is intended for demonstration purposes only, as mentioned in the developer's article. Inline colors are not displayed by the extension, but it still serves as a useful tool for analyzing the color palette of a webpage.

Overall, WhatColor is a simple yet effective Chrome extension that fulfills its purpose of identifying colors on web pages. It provides a convenient solution for web developers and designers, helping them streamline their workflow and improve their design process.