Examine source code of Listening Mode Switcher

{
  "manifest_version": 2,
  "name": "Listening Mode Switcher",
  "version": "1.1",
  "description": "Switch the webpage to a dark mode for better listening experience.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icons/icon-48.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{7dcb3150-2aba-4a60-bae9-4938ea7871c2}"
    }
  }
}