Google 在 TC39 中的提议
They argue that new features are placing a performance and security burden on JS engines, which puts the implementors at odds with JavaScript developers - who are demanding new syntactic sugar (apparently). By splitting the standard, Google hope that JSSugar could continue to evolve quickly while JS0 grows more gradually.
大致意思是,现有标准 javascript 将成为 JSSugar ,其继续丰富其语法特性,而真正运行在浏览器的 js 将成为 JS0,由 webPack 编译,其专注于性能和运行时友好。