Examine source code of MIA Dark Mode

{
  "manifest_version": 2,
  "name": "MIA Dark Mode",
  "version": "1.0",
  "description": "Enables dark mode on the Marxist Internet Archive.",
  "icons": {
    "128": "marx128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "marx128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.marxists.org/*"
      ],
      "js": [
        "darkmode.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eacabd96-a2df-4c75-9e4a-d35e0f933d9d}"
    }
  }
}