As a reminder, the rollup CSS and JS are compilations of many independently versioned components and is likely to contain changes that may disrupt the look of your site. We advise testing. Even better is to build your own CSS rollup from the npm sources, you can find a guide here.
Initial React support
While full React and Angular support remain goals with an unspecified date on the VF roadmap, we're trialing an initial approach to support React by wrapping the precompiled Angular templates.