Examine source code of Detector Whats Font

{
  "version": "1.3.0",
  "background": {
    "scripts": [
      "js/service-worker.js"
    ]
  },
  "content_scripts": [
    {
      "all_frames": false,
      "js": [
        "js/contents.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "64": "img/WF_64.png",
    "128": "img/WF_128.png",
    "256": "img/WF_256.png",
    "512": "img/WF_512.png"
  },
  "browser_action": {
    "default_icon": {
      "64": "img/WF_64.png",
      "128": "img/WF_128.png",
      "256": "img/WF_256.png",
      "512": "img/WF_512.png"
    }
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "contextMenus"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self';",
  "web_accessible_resources": [
    "css/wf.css"
  ],
  "options_ui": {
    "page": "html/setting.html",
    "open_in_tab": true
  },
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "minimum_chrome_version": "88",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c0bf4161-18c5-4476-a6c0-f7f5dd07b007}"
    }
  }
}