I'm very new to writing browser extensions, and at the moment I'm creating a little script that enhances Oracle BI for my company. It basically just changes a bit of things in the DOM, like adding an icon to a tab, depending on which url it is on (at least for now), and it works well. Here is a manifest.json for now:

manifset.json

{

  "manifest_version": 2,
  "name": "BI+",
  "version": "1.0",

  "description": "Zestaw dodatków wzbogacających funkcjonalność Oracle BI.",

  "icons": {
    "48": "icons/border-48.png"
  },

  "content_scripts": [
    {
      "matches": ["*://*/analytics/saw.dll?IBotSummary*"],
      "js": ["scripts/agent_edit.js"]
    },
    {
      "matches": ["*://*/analytics/saw.dll?EditDashboard*"],
      "js": ["scripts/dashboard_edit.js"]
    }
  ]

}

So for every different type of page I will have a separate script, and as you can imagine that means reusing a lot of code. So I've created a separate module, utilities.js, to pack all the functions I'm reusing often:

/icons
/scripts
    ++ utilities.js
    ++ agent_edit.js
    ++ dashboard_edit.js"
manifest.json

For now it is just a simple hello_world, and I can't event get that to work:

export function hello_world (){
  console.log('HELLO WORLD');
}

and my scripts/agent_edit.js is basically that (very simplified):

import { hello_world } from "./utilities.js";

function _some_async_awaiting_for_element() {
    main()
}

function main () {
    hello_world()
    add_icon_to_tab() # I want to move this to utilities.js once I get it to work
    
}

And as soon as I do that import in this content script, not even the hello_world() function call, this content script just does not fire up on the correct website. I checked every possible way of importing on mozilla docs: Mozilla Docs.

I thing it might have something to do with this line in the docs, but I'm not sure how to implement it when basically my extension does not include a DOM:

The import statement cannot be used in embedded scripts unless such script has a type="module".

How would one go about importing modules in this type of extension?