Riff stands for "Resource Interchange File Format". It is a generic file format used to store data seperated in chunks. You can easily know more with the Wikipedia page.
Riff file format has a well known viewer that has been here for a long time : Riffpad but I wanted to do mine (and improve it).
The building files are generated by premake using the description file located inside Scripts folder. You can use the pre-made scripts located inside the same directory to generate the executable.