[https://hacks.mozilla.org/2017/10/the-whole-web-at-maximum-fps-how-webrender-gets-rid-of-jank/ WebRender]: With WebRender, we want web apps to run at a silky smooth 60 frames per second (FPS) no matter how big the display is or how much of the page is changing from frame to frame. Initial releases will be for selected Nvidia GPUs. (Firefox 64, limited roll-out.)
[https://mozillagfx.wordpress.com/2018/01/09/retained-display-lists/ Retained Display List]: Gecko will retain the display list between paints, only building a new display list for the parts of the page that changed since we last painted and then merge the new list into the old to get an updated list. (Firefox 61)