"IntersectionObserver is a very straight-forward technology. It has a pretty good support in the modern browsers and if you want to implement it for browsers that still (or won’t at all) support it, of course, there is a polyfill for that. But all in all, this is a great technology that allows us to do all sorts of things related to detecting elements in a viewport while helping to achieve a really good performance boost."

"Quantum Render (or WebRender) is a major graphical system overhaul that’s coming to Firefox this year, and it promises hardware-accelerated painting of web content with huge performance wins."