Examine source code of Scrollbar Lens

{
  "manifest_version": 2,
  "name": "Scrollbar Lens",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "version": "0.0.3",
  "author": "emvaized",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "index.js"
      ],
      "css": [
        "index.css"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "<all_urls>"
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "scrollbar_lens@emvaized.dev"
    }
  }
}