Also TC39's efforts in all of JavaScript just about ever since. ActionScript's ES4 efforts left a lot of scars and that "lost version" of JavaScript is quite influential in the very least for how much ES2015+ avoids ES4/ActionScript ideas/problems/concerns as much as it learns from them and eventually reincorporates some of them.
Arguably HTML5 and JS to get both in a state where Flash wasn't needed. Not just for what Flash is famous for either. I used it a lot for "copy this text in a div to the clipboard" when browsers were all over the place on support for that.