The site was moved from a host that got a D rating on TTFB from whatever precursor to lighthouse he's using here onto an edge cached CDN. I expect the distance

The site was moved from a host that got a D rating on TTFB from whatever precursor to lighthouse he's using here onto an edge cached CDN. I expect the distance to server is helping but most of the improvement is from github pages having a pretty substantial built-in slowdown at the time (this is a 2014 article).