Tools > Context Browser brings up the context browser, which is like the system browser, but shows user-defined values rather than built-in ones. Notice how, once displayed, a context browser automatically keeps itself up to date with any new bindings you make. Try declaring a new function in the listener: it is added to the Entries pane automatically.
Like the system browser, the context browser also allows filtering through its own Usage > Tool Settings > Browser Filters... dialog.
In addition to the features of the system browser, the context browser allows you to inspect a value you have defined. Select a value in the context browser and choose Usage > Inspect. An inspector appears, showing details of the value in the usual way.