This is in the very early stages of development. Currently for gyul I use file called crate.js, which is just a big JS object, to hold all of the main data and content for my site. As I'm looking to also use gyul for longer writing, which means this needs to change. It's not the most human readable format.
The current plan is to have the file be a tabular file that is more human readable. There will also be a parsing library involved that will be able to parse patterns and symbols to quickly create links, bold text, etc.