The link to “open press” was a bit confusing since the website no longer mentions that name, boasting an open source knowledge graph for LLM agents now, but with a little jumping around I found the empty git repo with the feature list quoted in the blog
Aligning Automattic's Sponsored Contributions to WordPress
https://news.ycombinator.com/item?id=42650138
WordPress: Joost/Karim Fork
https://news.ycombinator.com/item?id=42662801