Examine source code of Temporary Mobile View

{
  "manifest_version": 3,
  "version": "0.2.3",
  "name": "Temporary Mobile View",
  "description": "View current page in the mobile-friendly format by spoofing Android or iOS user-agent string on request header and JavaScript sides",
  "permissions": [
    "declarativeNetRequestWithHostAccess",
    "storage",
    "contextMenus"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png",
    "256": "data/icons/256.png",
    "512": "data/icons/512.png"
  },
  "homepage_url": "https://webextension.org/listing/mobile-view.html",
  "action": {},
  "background": {
    "service_worker": "worker.js",
    "scripts": [
      "worker.js"
    ]
  },
  "options_ui": {
    "page": "data/options/index.html"
  },
  "commands": {
    "_execute_action": {
      "description": "Press the action button"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ed915aab-7a3a-4b36-9733-e9c2724f64d9}",
      "strict_min_version": "128.0"
    }
  }
}