Examine source code of Image Downloader

{
  "manifest_version": 2,
  "name": "Image Downloader",
  "version": "1.0",
  "description": "Download all images from a webpage individually or as a ZIP file.",
  "permissions": [
    "activeTab",
    "downloads"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{46f1dee2-bef8-4d8a-ab1e-3f8c1eaf876e}"
    }
  }
}