There is one.

https://github.com/unacms/una-vendor-test/wiki

The code in this repo is a very basic module called 'test'. It functions and prints hello world defined by a studio setting. You must read all the developer stuff leading up to the module creation to understand the module structure and code semantics.

And I started a thread about developing modules, if we could ask our questions under one thread I believe it will be easier for others to follow.