Examine source code of eBay Time Left

{
  "manifest_version": 2,
  "name": "eBay Time Left",
  "version": "1.5",
  "author": "Jonathan McCann",
  "homepage_url": "https://github.com/jonathanmccann/ebay-time-left",
  "description": "This Firefox addon will add the time left of the currently viewed eBay auction to the tab's title. No more missing auctions because you forgot the tab was open!",
  "permissions": [
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.ebay.com/*",
        "*://*.ebay.ca/*",
        "*://*.ebay.co.uk/*",
        "*://*.ebay.at/*",
        "*://*.ebay.com.au/*",
        "*://*.ebay.be/*",
        "*://*.ebay.ch/*",
        "*://*.ebay.de/*",
        "*://*.ebay.es/*",
        "*://*.ebay.fr/*",
        "*://*.ebay.ie/*",
        "*://*.ebay.it/*",
        "*://*.ebay.nl/*"
      ],
      "js": [
        "timeLeft.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5c0e6780-98ca-4708-9d89-5c7db7b12582}"
    }
  }
}