The views are all just webviews. You can find all of the pages in the app/src/main/assets/pages folder, it's all html and css.

Their package name is also still com.example, their target sdk doesn't match their compile sdk, and also neither match with the target sdk in their AppManifest.xml.

So I'm guessing this is just someone who isn't really familiar with java or native android views or something, so just decided to build it in something they do know instead.