When writing plugins, you will often find that you are creating a number of plugins that only differ in some respects, but have a lot more in common. For instance, for plotting, there are a number of generic R options that can be used with mostly all types of plots. Should you create a GUI and JS-template for those over and over again?

Obviously that would be quite a hassle. Fortunately, you do not have to do that. Rather you create the common functionality once, and later you can embed it into several plugins. In fact it is possible to embed any plugin into any other plugin, even if the original author of the embedded plugin never thought, somebody would want to embed their plugin into another one.