Plugins are special Perl Scripts that interact directly with Understand, they come in two flavors, Graphs and Interactive Reports. They can reference the entire Project, or a specific entity, depending on what the author intended. They can be as simple or complex as your imagination. There are API Tutorials that walk through creating Custom Graphs and creating Interactive Reports. If you haven’t already, we suggest you start there. More details on the Perl API Getting Started with the Perl API and more details on the Python API Getting Started with the Python API.
This custom graph modifies the call tree to show the complexity of each function (darker=more complex)
Be aware that often generating graphs for large projects can be very resource intensive, and in some cases the system can be non-responsive for a long period of time while the graphs are generated.
We have a public git repository for many plugins here.