Examine source code of Darggle

{
  "manifest_version": 2,
  "name": "Dark Mode Toggle",
  "version": "1.0",
  "description": "Adds a toolbar button to toggle dark mode on all active tabs using CSS filter inversion. Version 1.0: Basic toggle using invert and hue-rotate filters.",
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Toggle Dark Mode"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{36dc5a1d-be59-4a6e-8c99-9214279c71f5}"
    }
  }
}