Examine source code of Grail Finder

{
  "manifest_version": 2,
  "name": "Grail Finder",
  "version": "1.0",
  "description": "eBay researching tool",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "48": "/icons/grail-finder-48.png",
    "96": "/icons/grail-finder-96.png"
  },
  "background": {
    "scripts": [
      "/scripts/ExtPay.js",
      "/scripts/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://extensionpay.com/*"
      ],
      "js": [
        "/scripts/ExtPay.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "Grail Finder",
    "default_popup": "popup/popup.html"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Shift+G"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{754949bd-42cf-4359-9df3-d3d375428636}"
    }
  }
}