Examine source code of Dark Mode Switcher

{
  "manifest_version": 2,
  "name": "Dark Mode Switcher",
  "version": "1.0",
  "description": "Instantly toggle dark mode on any website with one click.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    },
    "default_title": "Toggle Dark Mode"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "applications": {
    "gecko": {
      "id": "darkmode-switcher-2742@example.com",
      "strict_min_version": "60.0"
    }
  }
}