Examine source code of Sky Timer

{
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "19": "events_19.png",
      "38": "events_38.png",
      "50": "icon_50.png",
      "128": "icon.png"
    },
    "default_popup": "index.html",
    "default_title": "Sky Timer"
  },
  "description": "Sky timer. London Big Ben, Pockemon or sample sounds! Don't miss your time.",
  "icons": {
    "128": "icon.png"
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAkgLwKeGb/DqEMtTccI40ZZbDeX8EiXKf859QMoPc29FDGhll/9diygOlrKO+ffj1TMdEklltSZE7I37pvmFN8jtoyljLwCRv88RgCR2svN8BajuBPirsS1x5iYBlisIzqZrNvjIM/aShoWW2/c3PyeFEF0LJyrBmHgecjhPMs49h9b0YacocidmGnD1LdmnWY6ORKxQ0QpdvprPsHGfnnFE4W8G+2y7Mc8N4R21IBabw+H6d/PK5VLXdkBFYMMx7nd+TIAjUGiePOmJs+uQ8zJFSPhhJlh5twuSZsOtqz0UUcYoA6OcK6YrdGMPOAfPPDJFQvjcnISIwKQ+LC/nmRQIDAQAB",
  "manifest_version": 2,
  "name": "Sky Timer",
  "offline_enabled": true,
  "permissions": [
    "alarms",
    "contextMenus",
    "cookies",
    "notifications",
    "http://developer.chrome.com/*"
  ],
  "short_name": "Sky Timer",
  "update_url": "http://clients2.google.com/service/update2/crx",
  "version": "1.8"
}