I am curious what was possible with yaml+md files that was impossible with flat file CMS. Afaik flat file CMSes are basically glorified .md editors.

The markdown didn’t help with anything that CMS couldn’t do. But special sections of pages would render differently based on the yaml configs.

You may think of it as: for each page, the yaml contained the React props to render. I d write the the main components, and the user would inject content through yaml as they saw fit.