## Summary
The `react-devtools-fusebox` private package is used in the React Native
DevTools (Fusebox) frontend by checking build artifacts into RN's
[fork]([`facebookexperimental/rn-chrome-devtools-frontend`](https://github.com/facebookexperimental/rn-chrome-devtools-frontend))
of the Chrome DevTools (CDT) repo - see
https://github.com/facebookexperimental/rn-chrome-devtools-frontend/pull/22.
Currently, the CDT fork also includes a [manually written TypeScript
definition
file](1d5f8d5209/front_end/third_party/react-devtools/package/frontend.d.ts)
which describes `react-devtools-fusebox`'s API. This PR moves that file
into the React repo, next to the implementation of
`react-devtools-fusebox`, so we can update it atomically with changes to
the package.
As this is the first bit of TypeScript in this repo, the PR adds minimal
support for formatting `.d.ts` files with Prettier. It also opts out
`react-devtools-fusebox/dist/` from linting/formatting as a drive-by
fix.
For now, we'll just maintain the `.d.ts` file manually, but we could
consider leveraging
[`flow-api-translator`](https://www.npmjs.com/package/flow-api-translator)
to auto-generate it in the future.
## How did you test this change?
Build `react-devtools-fusebox`, observe that `dist/frontend.d.ts`
exists.
## Summary
Stacked on https://github.com/facebook/react/pull/28552. Review only the
[last commit at the
top](c69952f1bf).
These changes add new package `react-devtools-fusebox`, which is the
entrypoint for the RDT Frontend, which will be used in Chrome DevTools
panel. The main differences from other frontend shells (extension,
standalone) are:
1. This package builds scripts in ESM format, this is required by Chrome
DevTools, see webpack config:
c69952f1bf/packages/react-devtools-fusebox/webpack.config.frontend.js (L50-L52)
2. The build includes styles in a separate `.css` file, which is
required for Chrome DevTools: styles are loaded lazily once panel is
mounted.
