Examine source code of Metaview

{
  "manifest_version": 2,
  "name": "Metaview",
  "version": "1.1",
  "description": "View social meta tags for a website",
  "homepage_url": "https://github.com/timheap/metaview",
  "icons": {
    "16": "assets/logo-16.png",
    "32": "assets/logo-32.png",
    "48": "assets/logo-48.png",
    "96": "assets/logo-96.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "assets/logo-16.png",
      "32": "assets/logo-32.png",
      "48": "assets/logo-48.png",
      "96": "assets/logo-96.png"
    },
    "default_title": "View meta tags",
    "default_popup": "popup/metaview.html"
  }
}