Core plugin on GitHub
One of fman's biggest strengths in comparison to other file managers is its plugin system. It enables anybody to customize and extend fman in very powerful ways.
To ensure that the plugin API is stable and expressive enough for real world use, fman itself implements all basic features in a plugin called Core. This plugin has been distributed as a part of fman for a long time, and plugin developers were encouraged to look at it for inspiration. The problem was, its sources were hidden deep in fman's installation directory, and so not exactly easy to peruse.
Several people requested that the source code of the Core plugin be made available online for easier browsing. Your wish is my command: The sources are now on GitHub. They make up a sizable 30% of fman's entire code base. Enjoy! :-)