Examine source code of NASA Images

{
  "manifest_version": 2,
  "name": "NASA Images",
  "version": "1.2",
  "description": "Watch some of the most recent NASA images.",
  "icons": {
    "48": "icons/nasa-48.png"
  },
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "bg/fetcher.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/nasa-32.png",
    "default_title": "NASA Images",
    "default_popup": "popup/popup.html"
  }
}