Examine source code of Darkdocs

{
  "name": "Darkdocs",
  "version": "0.5resigned1",
  "description": "Darkens up Google Docs.",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/*"
      ],
      "css": [
        "style.css"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "name": "Click to toggle Darkdocs on or off"
  },
  "icons": {
    "128": "icon.png"
  },
  "applications": {
    "gecko": {
      "id": "darkdocs@darkdocs.com"
    }
  },
  "manifest_version": 2
}