Examine source code of Quick Translator Premium

{
  "manifest_version": 2,
  "name": "Dark Mode Toggler",
  "version": "1.0",
  "description": "Switch any website to dark mode instantly.",
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "dark_mode_toggler@addon.dev"
    }
  }
}