Examine source code of v-iframe

{
  "name": "Vframe",
  "version": "1.0.1",
  "manifest_version": 2,
  "description": "Extract all iframes, videos, audios and photos of any website.",
  "icons": {
    "32": "32.png",
    "64": "64.png",
    "128": "128.png",
    "512": "512.png"
  },
  "browser_action": {
    "default_title": "Vframe",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "https://*/*"
  ],
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "https://*/*"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{def6afa4-cdaa-40b3-88c5-b6319c7ce448}"
    }
  }
}