Looking at the HTML for the blog post section of the site, it's not what's advertised, or they haven't implemented it yet as it's just the Google redirect.

    <script>document.referrer.startsWith("https://news.ycombinator.com")&&(console.log("Hacker News is becoming worse than 4chan. Do better."),document.location="https://google.com")</script>

EDIT: Yes, it's the old redirect added in March: https://github.com/AsahiLinux/AsahiLinux.github.io/commit/a7...

EDIT2: per this new commit not yet deployed, the site hides the text but makes it visible if you've visited the HN submit page through a CSS trick: https://github.com/AsahiLinux/AsahiLinux.github.io/commit/5c...