I will try to explain this feature on an example. In an application there are a few classes that has Draw methods without a parameter. The classes are Point, Triangle and Circle. In another php file there is a varibale $shape, where the Draw method is used.
In the case when NetBeans are not able to find out the type of the $shape variable and you want to navigate to the Draw method declaration, then it looks for all Draw methods with the same signature that are available in all classes in the project. In this example there are tree classes with Draw method without a parameter and all these classes are offered and you can select in which you want to jump. If there is only one class that has the Draw method, then it jumps to the Draw method declaration directly.
For navigation to the Draw method declaration you can place caret into Draw method name and press shortcut CTRL+B or you can use the hyperlink functionality (push CTRL and place mouse cursor over the Draw method name and click). You can also use main menu Navigate -> Go to Declaration or context menu in the editor.