Nope not a tutorial - but the code is nice and clear making it easy to work through and make changes/ add features in as a good learning exercise. The Lite editor plugins also give a good modular way to understand how specific features are implemented and to experiment with etc. The implementation overview (linked in post above) gives a great understanding of what is happening where. Overall its a really nice starting point for playing with the code base and thinking about how to extend or modify for your own use.
It includes lua 5.2 and SDL. On top of that, it's a few c files to handle input and rendering, and a set of neatly written lua modules for the logic.
Repo and author write-up:
https://github.com/rxi/lite
https://rxi.github.io/lite_an_implementation_overview.html