GitHub TOC Sidebar is a Chrome add-on developed by Reorx that enhances the accessibility of GitHub project readmes. This free add-on utilizes the built-in Table of Contents (TOC) component in GitHub to provide a convenient sidebar that sticks to the right side of the page. With GitHub TOC Sidebar, users can easily view the outline of the content and navigate between different sections of a long readme.

When viewing the home page of a GitHub project, the TOC sidebar automatically opens and sticks to the right side of the page as you scroll down. This makes it much easier to navigate through the various sections of the readme. The add-on works specifically with projects that have a readme file written in a markup language such as Markdown or RST, and have headings that split the content into multiple sections with titles.