Examine source code of Trade Value Calculator

{
  "manifest_version": 2,
  "name": "Trade Value Calculator",
  "version": "2.0.1",
  "description": "Interactive Fantasy Football trade value calculator with values calculated by /u/PeakedInHighSkool",
  "icons": {
    "48": "icons/trade_48.png"
  },
  "permissions": [
    "<all_urls>",
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/trade_48.png",
    "default_title": "Trade Values",
    "default_popup": "popup/popup.html"
  }
}