Examine source code of KeyboardOnPage

{
  "name": "KeyboardOnPage",
  "description": "Facility for providing keyboard built-in to a web page.",
  "version": "2.0",
  "permissions": [
    "alarms",
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "optional_permissions": [
    "scripting"
  ],
  "background": {
    "page": "background-page.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "extra/jquery-3.6.0.min.js",
        "extra/content_common.js",
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [],
      "extension_ids": [
        "*"
      ],
      "matches": [
        "*://*/*"
      ]
    }
  ],
  "action": {
    "default_icon": "default-64.png",
    "default_title": "KeyboardOnPage"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; upgrade-insecure-requests;"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "a0@."
    },
    "gecko_android": {}
  },
  "manifest_version": 3
}