Examine source code of Reading Progress Bar

{
  "manifest_version": 2,
  "name": "Reading Progress Bar",
  "version": "1.1resigned1",
  "description": "Adds a reading bar to webpages.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "jquery-3.2.1.min.js",
        "progress-bar-extension.js"
      ],
      "css": [
        "progress-bar-extension.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ab81ae3f-aaef-4d6a-918c-2697e8e9ab57}"
    }
  }
}