Maatkit has two primary developers, and an active community with many people contributing in various ways. You can contact the developers and other community members through the project’s mailing list.
Daniel is the main developer, and has been working on Maatkit since 2008. He is the author of many powerful tools, including the venerable mysqlreport. He works for Percona, developing Maatkit full-time.
Baron created Maatkit in 2006 to solve his own problems. He doesn’t write very much code these days, but he is still actively involved, especially in defining new tools and features. He is a consultant at Percona, and tries to help make life easier for DBAs, users, and other consultants.