This is neat. When I started with WP over 10 years ago I would use a theme similar to this. Both to teach myself WP theme building and because I wanted something as lean as possible. I'd build my HTML5 template and then paste in the bare minimum PHP.
Then my clients started asking for "visual builders" and now I build sites with a robust (read: bloated) theme. I'm not thrilled, but the point of client work is to make the client happy!
Neat! Any sample website we can visit to see this in action? Or did I missed it in the page above?