That is the standard Eclipse OSGi plug-in architecture that "wraps" your Web Module as a Red App, and where you configure and implement your Java services, and extensions points.

In particular to Web Modules development, is the presence of   \web-src and \web folders at root level of your plug-in, which will be respectively used for developing and runtime provisioning of your Web Module.

For more information on how to create a Red App Eclipse plug-in using Dev Tools inside the Eclipse, please consult:

More about Red App: What is a Red App and Red App Bundle.