@babel/preset-env, useBuiltIns: 'usage' and regeneratorRuntime

https://babeljs.io/docs/en/babel-preset-env#usebuiltins-usage says it adds polyfills. But I assume it also adds `regeneratorRuntime` (which is not a polyfill)? Should that be explicit somewhere in the `usage` part? Since I assume `usage` doesn't do anything else than to add `core-js` Polyfills and the funciton `regeneratorRuntime`?

Start with the useBuiltIns: 'usage' section at the linked Babel preset-env documentation page and verify what it adds, including core-js polyfills and regeneratorRuntime. Update the documentation to state the behavior explicitly, with the wording considered done when the scope of usage is unambiguous.

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