Examine source code of Devil Debugger

{
  "manifest_version": 2,
  "name": "Devil Debugger",
  "version": "1.0",
  "description": "Toggle clean visual borders to debug HTML structure. Built for frontend devs who want hell-level precision.",
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icons/128.png"
    }
  },
  "applications": {
    "gecko": {
      "id": "starvicki2002@gmail.com",
      "strict_min_version": "91.0"
    }
  }
}