Change manifest to conform to browser extension

In addition to a mobile and web app, I need to build a companion browser extension. The extension will re-use much of the code in the web app, so naturally I’d like to configure expo to spit out a bundle that will work.

I’ve been able to use webpack.config.js to generate different endpoints and I’ve also added a custom manifest.json into the root web directory. expo build:web picks it up, but overwrites the icons node in the manifest.

I need it to be:

...
"icons": {...}
...

But the builder seems to require the value to be an array:

...
"icons": [...]
...

Can anyone tell me how I might be able to configure/overwrite this so the expo builder doesn’t inject the PWA icons array?