The difficulty comes from the fact that chrome extensions can only make external http requests through the background.js
file which is separate from the extension and all communication between the two are serialized, which removes files.
I've found some solutions from 1++ years ago, but all seem to be very hacky and not working anymore anyway (as tends to happen to hacky solutions).
So I am left wondering if it is possible at all to upload files from a chrome extension that opens on any website.