Interested in contributing to the WordPress.orgWordPress.org The community site where WordPress code is created and shared by the users. This is where you can download the source code for WordPress core, plugins and themes as well as the central location for community conversations and organization. https://wordpress.org/ mobile apps? Have questions on how something works? Check out the links in the sidebarSidebar A sidebar in WordPress is referred to a widget-ready area used by WordPress themes to display information that is not a part of the main content. It is not always a vertical column on the side. It can be a horizontal rectangle below or above the content area, footer, header, or any where in the theme. and come join us in #mobile in the Slack chat system. The Handbook is in need of some updates but we primarily use GitHubGitHub GitHub is a website that offers online implementation of git repositories that can can easily be shared, copied and modified by other developers. Public repositories are free to host, private repositories require a paid subscription. GitHub introduced the concept of the ‘pull request’ where code changes done in branches by contributors can be reviewed and discussed before being merged be the repository owner. https://github.com/ Issues for communication regarding issues and changes and SlackSlack Slack is a Collaborative Group Chat Platform https://slack.com/. The WordPress community has its own Slack Channel at https://make.wordpress.org/chat/. for any general questions.