Examine source code of Mobile View Toggle

{
  "manifest_version": 2,
  "name": "Mobile View Toggle",
  "version": "4.7",
  "description": "Open the active tab in a mobile-sized window with a mobile user-agent. Switch device, rotate, and capture screenshots from an in-window toolbar.",
  "browser_specific_settings": {
    "gecko": {
      "id": "mobil-gorunum@yasinkeles.local",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "tabs",
    "activeTab",
    "webRequest",
    "webRequestBlocking",
    "downloads",
    "storage",
    "clipboardWrite",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-bar.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "96": "icon-96.png",
    "128": "icon-128.png"
  },
  "browser_action": {
    "default_title": "Toggle Mobile View",
    "default_icon": {
      "16": "icon-16.png",
      "32": "icon-32.png",
      "48": "icon-48.png"
    }
  },
  "commands": {
    "open-mobile-view": {
      "suggested_key": {
        "default": "Alt+Shift+M",
        "mac": "Alt+Shift+M"
      },
      "description": "Toggle mobile view"
    },
    "screenshot-mobile": {
      "suggested_key": {
        "default": "Alt+Shift+S",
        "mac": "Alt+Shift+S"
      },
      "description": "Capture the mobile window"
    }
  }
}