Yep, the configuration for Workbox lives here:

https://github.com/facebook/create-react-app/blob/8b0dd54c7a7488d46a43ff6d1c67a6b41c31feb1/packages/react-scripts/config/webpack.config.js#L674

https://github.com/GoogleChrome/workbox/blob/7fde87915e1e122b24e18f9e214a31d6a1986820/packages/workbox-precaching/src/precache.ts#L56-L57

Do you know where in create-react-app the configuration for Workbox lives? It would be good to document that here also.

Yeah, that makes sense, specifically this line: workbox.precaching.precacheAndRoute(self.__precacheManifest, {});

It's a little hard to read, but it looks like https://storage.googleapis.com/workbox-cdn/releases/4.3.1/workbox-sw.js is doing some Workbox set up.

It's looking maybe like the answer to "who is caching our files" is Workbox?