Examine source code of Dark Mode on off

{
  "manifest_version": 2,
  "name": "Dark Mode Simple",
  "version": "1.1",
  "description": "Active/désactive un dark mode sur tous les sites.",
  "permissions": [
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{45503b11-a4f2-4329-9678-094a1ac2d890}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Dark Mode",
    "default_icon": "icon.png"
  }
}