Examine source code of K2s URL Extractor

{
  "name": "URL Extractor",
  "version": "1.0.1",
  "manifest_version": 2,
  "description": "Extract all URLs from any web page instantly. Great for research, scraping, or organizing links from a site",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "/js/background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "/js/findURLs.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "activeTab",
    "tabs",
    "http://*/",
    "https://*/",
    "<all_urls>",
    "downloads"
  ],
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{776e3e6b-4a60-40f9-9c2e-736eabaff507}"
    }
  }
}