@ScottDurow It seems like there should be some way to hook in while putting that customization in the project file structure (and therefore source control), avoiding having to modify the files sitting in $/node_modules/*. I will make sure the CLI team gets the community feedback around this, but if it can be put into that Idea post, it would make that easier.
Shouldn't this be a part of the standard package since this is how Babel 7 will support browsers? The old "polyfill" is a Babel 6 recommendation.
As of Babel 7.4.0, this package has been deprecated in favor of directly including core-js/stable (to polyfill ECMAScript features) and regenerator-runtime/runtime (needed to use transpiled generator functions):