Examine source code of whyEXT Dark Mode

{
  "manifest_version": 3,
  "name": "whyEXT Dark Mode",
  "version": "0.1.0",
  "description": "Simple per-domain dark mode toggle.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_title": "Dark Mode",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png"
    },
    "default_popup": "popup.html"
  },
  "options_page": "options.html",
  "permissions": [
    "storage",
    "activeTab",
    "scripting",
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "dark-mode@whyext.local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}