Examine source code of Humbleload

{
  "manifest_version": 2,
  "name": "Humbleload",
  "version": "1.2",
  "description": "A Browser Plugin to download all eBooks in a HumbleBundle.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.humblebundle.com/downloads*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "webRequest",
    "downloads",
    "*://*.humblebundle.com/downloads*"
  ]
}