What about async/await? Do we have the right combination of plugins for it after this change?

According to the source code of babel-preset-es2017, it transforms async/await to generators using babel-plugin-transform-async-to-generator. After that, create-react-app can polyfill generators by babel-plugin-transform-runtime, see config/babel.dev.js and config/babel.prod.js.

This probably means babel-plugin-syntax-async-functions is no longer needed?

Yes, because a Babel transform enables the corresponding syntax plugin.

latest also contains transform-async-to-generator via 2017.
Do we still need the regenerator transform for async/await in this case?
What is the best way to enable both generators and async/await?

According to the documentation of babel-plugin-transform-regenerator, there are 3 regenerator transform options available: asyncGenerators, generators and async. I think that async should be set to false, but to be honest, I have no idea whether the value of asyncGenerators should be set to true or false. Maintainers of Babel may be able to help explaining the correct approach.

It looks like the term "async generator" may refer to an old proposal, so it could possibly be left untouched.

Thanks!

Sorry in advance for digging up an old PR, but there's a lot of context here about a particular change in .babelrc that caught my eye, specifically this. I was trying to understand the combination of transforms for async, and I came across this in babel-preset-es2015.

With the preset already setting async and asyncGenerators to false, do we really need to set it ourselves in babel-preset-react-app?

To be honest I don't remember. If this is still relevant can you file an issue?