Examine source code of GDT

{
  "manifest_version": 2,
  "name": "GDT",
  "short_name": "GitHub Dark Theme",
  "description": "A Dark theme for GitHub",
  "version": "1.0.2",
  "browser_action": {
    "default_icon": "icons/icon-96.png"
  },
  "applications": {
    "gecko": {
      "id": "{97e373a3-4c18-4a48-8787-1e591cf0be4d}"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.github.com/*"
      ],
      "css": [
        "css/github-dark.min.css"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  }
}