Examine source code of Show Title Tag Corner

{
  "version": "16.1.0",
  "background": {
    "scripts": [
      "js/service-worker.js"
    ]
  },
  "content_scripts": [
    {
      "all_frames": false,
      "js": [
        "js/content.js"
      ],
      "css": [
        "css/content.css"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_end"
    }
  ],
  "icons": {
    "32": "img/32.png",
    "64": "img/64.png",
    "128": "img/128.png",
    "256": "img/256.png"
  },
  "browser_action": {
    "default_icon": "img/64.png"
  },
  "options_ui": {
    "page": "html/setting.html",
    "chrome_style": false,
    "open_in_tab": true
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{ec26f646-040b-476a-b7d1-d5340cd24ed6}"
    }
  }
}