Examine source code of SEO Analyser

{
  "manifest_version": 2,
  "name": "SEO Analyser",
  "version": "1.0.2",
  "description": "Analyses webpage SEO metrics and provides detailed scoring",
  "author": "Tom",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "activeTab",
    "webNavigation",
    "tabs",
    "<all_urls>",
    "webRequest"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1c3eb3f2-5e40-4e3e-95ad-48039389367c}"
    }
  }
}