This is an experiment. Inspired by conversations between Helen Hou-Sandí and Mark Jaquith, this code was created to explore new ways of making blocks for WordPress that are simpler, more declarative, and less repetitive than custom-crafted React components.
Helen write about the thinking behind this idea in depth, and you should absolutely read that to understand what this is all about.
This is incomplete code. It is not meant for production. It requires PHP 7.4.
Blocky by Riad Benguella, who (completely coincidentally) was working on a very similar idea the same weekend this code was written.