If you're looking to read the J5e documentation, head over to j5e.dev.
If you're looking to contribute to the J5e documentation you've come to the right place.
The only documentation text managed in this repo are the pages found in getting-started, core-concepts, and the docs home page. The rest of the documentation text is managed in the J5e repository using JSDoc style inline comments.
The site is built using Eleventy and Liquid templates, with a little preprocessing on the JSDoc data in _data/module-pages.js