You have just installed an extension that contains three additional skins that provide additional look and feels that you can use in your ADF Faces applications. These skins are provided as examples.
There are three sub directories in there, one for each skin:
To learn more about applying a new skin in your application read
7.2.2 How to Add a Custom Skin to an Application
From the Oracle WebCenter Framework Developer's Guide
To learn more about developing your own skins read:
22.3 Using Skins to Change the Look and Feel
From the Oracle Application Development Framework Developer's Guide For Forms/4GL Developers