Examine source code of Multi Engine Searcher

{
  "manifest_version": 3,
  "name": "Multi Engine Search",
  "version": "1.0",
  "description": "Search using selected search engines from a browser action popup, with customization.",
  "icons": {
    "16": "icons/icon-16.png",
    "19": "icons/icon-19.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "scripting",
    "storage",
    "contextMenus",
    "tabs",
    "downloads"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "19": "icons/icon-19.png",
      "48": "icons/icon-48.png"
    }
  },
  "background": {
    "scripts": [
      "js/lib/encoding.min.js",
      "js/utils.js",
      "js/initialEngines.js",
      "js/background.js"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+9"
      },
      "description": "Open Multi Engine Search Popup"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4995fbb1-90ba-44d7-a125-6e4dd4ab840c}",
      "strict_min_version": "115.0"
    }
  }
}