Examine source code of Night Mode Switcher

{
  "manifest_version": 2,
  "name": "Night Mode Switcher",
  "version": "1.0",
  "description": "Toggle night mode (dark theme) on any website instantly.",
  "permissions": [
    "activeTab",
    "storage",
    "scripting",
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icon128.png"
    }
  },
  "icons": {
    "128": "icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{31a80f22-5a12-414d-bf10-500786d2bcef}"
    }
  }
}