Examine source code of browser-addon-custom-js

{
  "name": "browser-addon-custom-js",
  "version": "1.1.1",
  "description": "very experimental - please only use JS you can trust",
  "permissions": [
    "storage",
    "unlimitedStorage"
  ],
  "browser_action": {
    "default_popup": "structure.html",
    "default_icon": {
      "128": "icon.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "page.js"
      ]
    }
  ],
  "icons": {
    "128": "icon.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4c00456-0a90-4c5a-9946-e81ddc807e88}"
    }
  }
}