tl;dr:AVIF is a new royalty-free image format derived from the keyframes of AV1 video supported in Chrome 85, and others soon. Although initially skeptical, Jakes highlights advantages over existing formats.
tl;dr:None of sites are built on JS frameworks, they are mostly Drupal or Wordpress with lots of jQuery, none pre-load fonts. This article audits each site providing in-depth advice on performance improvements. 🏎️