GitHub has updated its project root URLs by removing the “/tree/default_branch” suffix, simplifying the structure of URLs. For example, what used to be http://github.com/mojombo/jekyll/tree/master is now streamlined to http://github.com/mojombo/jekyll. The previous URL format with “tree/master” will still function through a 301 redirect, ensuring continuity and ease of access for users. This change was announced by Chris Wanstrath, also known as @defunkt.