Examine source code of esmb

{
  "description": "Adds a new panel to the developer tools. The panel contains a script editor which allows you to write an ES6 module and execute it into the current window",
  "manifest_version": 2,
  "name": "esmb",
  "version": "1.5.6",
  "author": "Lcf.vs",
  "icons": {
    "16": "assets/img/icon.svg",
    "24": "assets/img/icon.svg",
    "32": "assets/img/icon.svg",
    "48": "assets/img/icon.svg",
    "128": "assets/img/icon.svg"
  },
  "background": {
    "page": "pages/background.html"
  },
  "permissions": [
    "<all_urls>"
  ],
  "devtools_page": "pages/devtool.html"
}