Examine source code of Quickle

{
  "name": "Quickle",
  "version": "1.0.0",
  "manifest_version": 2,
  "description": "Easily access Google Products",
  "homepage_url": "https://github.com/dagabey/Quickle",
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "firefox-images/icon-16.png",
    "48": "firefox-images/icon-48.png",
    "128": "firefox-images/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "unlimitedStorage"
  ]
}