React by itself doesn't do that, but CSS-in-JS libraries are fairly common in the React ecosystem, and most of them have random autogenerated class names.

Even though this is a good point, I am somewhat disappointed that people downvoted a trivially correct statement. React is arguably the most popular web framework and it definitely doesn’t do this, nor does anything about it make it especially make sense to do this. Not every React app uses styled components or a CSS in JS solution at all. Arguably, a fair bit don’t. Anything using Blueprint doesn’t entirely use CSS in JS.