Sure fooled me. I follow his Twitter account and there isn't much he hasn't got building with it at this point. UX comes later. Amazing it's the random work of one person

The author wrote WebKit’s allocator and worked on JavaScriptCore for over a decade. I really enjoyed his posts on the WebKit blog over the years like this one on the concurrent garbage collector (2017) https://webkit.org/blog/7122/introducing-riptide-webkits-ret...

I don’t think so much is fil-c itself, but from the looks of the diff it’s a new platform essentially. That can require porting existing software generally which you can read from the posted diff