Examine source code of Metric Unit Conversion Calculator

{
  "manifest_version": 3,
  "version": "1.3.6",
  "name": "__MSG_extName__",
  "short_name": "__MSG_extShortName__",
  "description": "__MSG_extDescription__",
  "default_locale": "en",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_title": "__MSG_extName__",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "64": "icons/icon64.png",
      "128": "icons/icon128.png"
    }
  },
  "background": {
    "scripts": [
      "js/config.js",
      "js/background-core.js",
      "js/background.js"
    ]
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "search",
    "cookies",
    "alarms",
    "webRequest",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://metricunitconversioncalculator.com/*",
        "*://*.metricunitconversioncalculator.com/*"
      ],
      "run_at": "document_end",
      "all_frames": false,
      "js": [
        "js/contentscript.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  },
  "chrome_settings_overrides": {
    "search_provider": {
      "name": "__MSG_extName__",
      "keyword": "__MSG_extKeyword__",
      "search_url": "https://search.metricunitconversioncalculator.com/search?q={searchTerms}",
      "favicon_url": "favicon.ico",
      "is_default": true
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b9cea876-e3a0-4ce1-9320-4855d0cc408e}",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}